Advanced lithium (li) ion and lithium sulfur (li s) batteries

ABSTRACT

This disclosure provides a lithium (Li) ion battery that includes an anode, a cathode positioned opposite to the anode, a porous separator positioned between the anode and the cathode, and a liquid electrolyte in contact with the anode and the cathode. The anode includes an electrically conductive substrate. A first film is deposited on the electrically conductive substrate. The first film includes a first concentration of carbon particles in contact with each other and defines a first electrical conductivity for the first film. Each of the carbon particles includes a plurality of aggregates formed of few layer graphene sheets. The plurality of aggregates form a porous structure configured to undergo a lithiation, which can include any one or more of an intercalation operation or a plating operation. The anode and the cathode can include an electroactive material. The porous structure can provide conduction between the few layer graphene sheets.

RELATED APPLICATIONS

This application is a continuation-in-part application and claimspriority to U.S. patent application Ser. No. 16/785,020, filed on Feb.7, 2020 and entitled “3D Self-Assembled Multi-Modal Carbon BasedParticle” and to U.S. patent application Ser. No. 16/785,076, filed onFeb. 7, 2020 and entitled “3D Self-Assembled Multi-Modal Carbon BasedParticles integrated into a continuous film layer,” both of which claimpriority to U.S. Provisional Patent Application No. 62/942,103, filed onNov. 30, 2019 and entitled “3D Hierarchical Mesoporous Carbon-BasedParticles Integrated into a Continuous Electrode Film Layer,” and U.S.Provisional Patent Application No. 62/926,225, filed on Oct. 25, 2019and entitled “3D Hierarchical Mesoporous Carbon-Based ParticlesIntegrated into a Continuous Electrode Film Layer,” all of which areassigned to the assignee hereof. The disclosures of all priorApplications are considered part of and are incorporated by reference inthis Patent Application.

TECHNICAL FIELD

This disclosure relates generally to producing carbon-based particles,and, more particularly, to incorporating the produced carbon-basedparticles into battery electrodes.

DESCRIPTION OF RELATED ART

Technological advances have enabled consumers to use electronic devicesin many new applications previously not possible. Such devices havealready become common, many of which rely on battery-supplied power andcontinue to increase in popularity. Filling the associated electricpower consumption demands, batteries—especially secondary batteries,such as rechargeable batteries, have emerged as a universal solution byallowing for portability and convenient continued device usage.

Challenges related to rechargeable battery performance persist,especially concerning both lifespan and cyclability have thereforeattracted ongoing innovation in lithium-ion, referred to in short formas Li-ion, technology. Conventionally, an intercalated Li compound canbe used as a formative material at the cathode paired with graphite atthe anode. Li-ion batteries, in contrast to other battery types, havebeen sought for usage in portable electronic devices due to theirrelatively high energy density and limited to no memory effect, such asthat encountered by traditional nickel-cadmium and nickel-metal hydriderechargeable batteries that lose their ability to store electricalcharge over multiple charge-discharge cycles involving partial dischargeand relatively low self-discharge. As a result, Li-ion batteries offermany of the benefits found in primary, such as non-rechargeable, Libatteries, including high charge density that results in longer usefullifespans, without the concerns of rapid discharge resulting inoverheating, rupture or explosion that may be encountered in Libatteries due to the highly reactive nature of Li metal.

To assist ongoing developments in Li ion battery specific capacity,cycle-ability, and power delivery, amorphous carbon has also beenconsidered with Li as a formative material to form Li ion batteryelectrodes. However, such electrodes continue to suffer from arelatively a low electrical conductivity and high charge transferresistance, which, in turn, results in a high polarization or internalpower loss. Conventional amorphous carbon-based anode materials also maytend to give rise to a high irreversible capacity, among creating otherpotential issues.

SUMMARY

This Summary is provided to introduce in a simplified form a selectionof concepts that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tolimit the scope of the claimed subject matter.

One innovative aspect of the subject matter described in this disclosurecan be implemented as a lithium (Li) ion battery including an anode, acathode positioned opposite to the anode, a porous separator positionedbetween the anode and the cathode, and a liquid electrolyte in contactwith the anode and the cathode. The anode includes an electricallyconductive substrate. A first film is deposited on the electricallyconductive substrate. The first film includes a first concentration ofcarbon particles in contact with each other that are configured todefine a first electrical conductivity for the first film. Each of thecarbon particles includes a plurality of aggregates formed of few layergraphene sheets. The plurality of aggregates forming a porous structureare configured to undergo a lithiation.

In some implementations, the lithiation includes any one or more of anintercalation operation or a plating operation. Each of the anode andthe cathode can include an electroactive material. The porous structureis configured to provide electrical conduction between contact points ofthe few layer graphene sheets. The porous structure can be configured tocontain a molten Li metal. The porous structure can be configured toreceive the liquid electrolyte, which can be configured to facilitatetransport of a plurality of Li ions within the porous structure.

In some implementations, a second film can be deposited on the firstfilm. The second film can include a second concentration of carbon-basedparticles. The second concentration of carbon-based particles isconfigured to provide a second electrical conductivity for the secondfilm that is lower than the first electrical conductivity. Theelectroactive material can reside in pores of one or both of the anodeand the cathode. The electroactive material can have a specific surfacearea (SSA) between approximately 1,635 m²/g and 2,675 m²/g. Theelectroactive material can include any one or more of pre-lithiated fewlayer graphene (FLG) sheets, pristine graphene, graphene oxide, reducedgraphene oxide, graphene fluoride, graphene chloride, graphene bromide,graphene iodide, hydrogenated graphene, nitrogenated graphene,boron-doped graphene, nitrogen doped graphene, chemically functionalizedgraphene, physically or chemically activated or etched versions thereof,sulfur-doped graphene, or electrically conductive polymer coated orgrafted versions thereof.

In some implementations, the porous structure can be defined by theaggregates independent of a binder and configured to be formed in asubstantially spherical shape having a dimension in any one or more ofin the range of 1-30 μm, <50 μm, or above 500 nm. The porous structurecan include an active Li intercalating structure configured toincorporate silicon (Si). The active Li intercalating structure can havea specific capacity of between approximately 730-3,600 mAh/g. Thechemically functionalized graphene can include a functional groupselected from quinone, hydroquinone, quaternized aromatic amines,mercaptan, disulfide, sulfonate (—SO₃), transition metal oxide,transition metal sulfide, or a combination thereof, including functionalgroups configured to react with or incorporate any one or more ofmagnesium (Mg), calcium (Ca), aluminum (Al), strontium (Sn), and zinc(Zn).

In some implementations, the electrically conductive substrate is acurrent collector, which can be at least partially foam-based orfoam-derived and is selected from any one or more of a metal foam, ametal web, a metal screen, a perforated metal, a sheet-based 3Dstructure, a metal fiber mat, a metal nanowire mat, an electricallyconductive polymer nanofiber mat, an electrically conductive polymerfoam, an electrically conductive polymer-coated fiber foam, carbon foam,graphite foam, carbon aerogel, carbon xerogel, graphene foam, grapheneoxide foam, reduced graphene oxide foam, carbon fiber foam, graphitefiber foam, and exfoliated graphite foam.

In some implementations, the current collector is formed as a foil. Theelectroactive material can include one or more of nanoparticles,nanodiscs, nanoplatelets, nano-coating, or nanosheets of an inorganicmaterial. The nanoparticles, nanodiscs, nanoplatelets, nano-coating, ornanosheets of an inorganic material can be selected from bismuthselenide or bismuth telluride, transition metal dichalcogenide ortrichalcogenide, sulfide, selenide, or telluride of a transition metal,boron nitride, or a combination thereof, wherein the nanoparticles,nanodiscs, nanoplatelets, nano-coating, or nano sheets have a thicknessless than 100 nm.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of the subject matter described in this disclosure are setforth in the accompanying drawings and the description below. Otherfeatures, aspects, and advantages of the subject matter will becomeapparent from the description, the drawings, and the claims.

FIGS. 1A through 1E show diagrams of a carbon-based particle withvarious defined regions for electrical conduction and ion transport; andFIG. 1F shows schematic diagrams representative of intermediate stepsfor the reduction of sulfur and/or the formation of polysulfides (PS).

FIGS. 1G and 1H show schematics for placement and/or intercalation of Liions in carbon lattices and structures.

FIG. 2 show schematics for cavities that are formed extending depth-wiseinto several of the adjacent stacked FL graphene layers.

FIG. 3 shows a schematic of a multi-layered carbon-based scaffoldedstructure.

FIG. 4A shows a schematic of the structure shown in FIG. 3 with lithium(Li) metal infused into nanoscale gaps therein.

FIG. 4B shows a schematic diagram of a series of plasma spray torchespositioned in a continuous sequence above a roll-to-roll (R2R)processing apparatus.

FIG. 5 shows an schematic diagram for an example Li ion or Li Selectrochemical cell.

FIG. 6A shows a schematic diagram of the incorporation of metal powdersinto a carbon particle for Li wetting and infiltration.

FIGS. 6B and 6C show schematic diagrams for chemically non-reactivesystems and chemically reactive systems, respectively.

FIG. 7 shows an example process workflow where molten Li metal isinfiltrated into void spaces between carbon agglomerations.

FIG. 8A shows an equation for a rate of infiltration a carbon-basedstructure.

FIGS. 8B and 8C show non-reactive and reactive systems regarding Liinfiltration into carbon structures.

FIG. 9 shows a flowchart depicting example operations of lithiating andalloying a carbon-based structure.

FIG. 10A shows a flowchart depicting example operations of preparing acarbon-based structure.

FIG. 10B shows a flowchart depicting example operations of preparing Limaterials.

FIG. 10C through FIG. 10P show flowchart depicting example operations offabricating an electrochemical cell electrode.

FIG. 11A through 11C show depicting example operations of preparing acarbon particle for lithiation.

FIG. 12 shows a flowchart depicting example operations of performing Liinfusion of a carbon particle.

FIG. 13 shows a schematic of an anode.

FIG. 14 shows a silicon and carbon anode performance over multiple usagecycles.

FIGS. 15 and 16 show schematics s related to an idealized cathodeconfiguration with lithium sulfide (Li₂S) nanoparticles in graphenedispersed therein.

FIGS. 17A and 17B show an enlarged portions of the carbon-basedparticles of FIGS. 1A through 1F.

FIGS. 18A through 18E are micrographs of portions of a carbon particles.

FIG. 19A shows a schematic of a 3D carbon-based cathode.

FIG. 19B shows a schematic diagram of a 3D carbon-based anode.

FIG. 20A shows discharge and charge cycles of an example Li Selectrochemical cell.

FIGS. 20B and 20C show battery performance charts for batteries equippedwith carbon-inclusive electrodes.

FIG. 21 shows Raman spectra for 3D N-doped FL graphene.

FIG. 22 shows schematic diagrams of bilayer graphene.

FIG. 23 shows a method for preparing a 3D scaffolded film.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

Various aspects of the novel systems, apparatuses, and methods aredescribed more fully herein with reference to the accompanying drawings.The teachings disclosed can, however, be embodied in many differentforms and should not be construed as limited to any specific structureor function presented throughout this disclosure. Rather, these aspectsare provided so that this disclosure will be thorough and complete, andwill fully convey the scope of the disclosure to those skilled in theart.

Based on the teachings herein one skilled in the art should appreciatethat the scope of the disclosure is intended to cover any aspect of thenovel systems, apparatuses, and methods disclosed herein, whetherimplemented independently of or combined with any other aspect of theinvention. For example, an apparatus can be implemented, or a method canbe practiced using any number of the aspects set forth herein. Inaddition, the scope of the invention is intended to cover such anapparatus or method which is practiced using other structure,functionality, or structure and functionality in addition to or otherthan the various aspects of the invention set forth herein. Any aspectdisclosed herein can be embodied by one or more elements of a claim.

Although some examples and aspects are described herein, many variationsand permutations of these examples fall within the scope of thedisclosure. Although some benefits and advantages of the preferredaspects are mentioned, the scope of the disclosure is not intended to belimited to benefits, uses, or objectives. Rather, aspects of thedisclosure are intended to be broadly applicable to a carbon-basedparticle self-nucleated in an atmospheric-pressure vapor flow stream ofa carbon-containing gas such as methane, the carbon-based particleincluding multiple electrically conductive three-dimensional (3D)aggregates of graphene sheets defining void spaces and ion conduitstherein, some of which are illustrated in the figures and in thefollowing description of the preferred aspects. The detailed descriptionand drawings are merely illustrative of the disclosure rather thanlimiting, the scope of the disclosure being defined by the appendedclaims and equivalents thereof.

Definitions Li-Ion Batteries

A Li-ion battery is a type of secondary, alternatively referred to as arechargeable, battery. Such battery technology has shown great promisein recent years as power sources that can lead to an electric vehicle(EV) revolution by facilitating the widespread implementation of EVsacross numerous applications. Accordingly, the development of newmaterials for various components of Li-ion batteries is the focus ofresearch in the field of materials science. Li-ion batteries power mostmodern portable devices and seem to have overcome psychological barriersof the consuming public against the use of such high energy densitydevices on a larger scale for more demanding applications, such as EVs.

Regarding operation, in Li-ion batteries, Li ions (Li+) migrate from thenegative electrode, also referred to as the anode, through anelectrolyte, which can be in any one or more of a liquid phase or a gelphase, to the positive electrode during discharge cycles and returnduring charging cycles. Conventional Li-ion batteries can use anintercalated Li compound as a formative material at the positiveelectrode and graphite at the negative electrode. Such batteries can becharacterized by their relatively high energy density measured as aspecific capacity having the units of milliamp hours per gram (mAh/g),no “memory-effect”—describing the situation in which nickel-cadmiumbatteries gradually lose their maximum energy capacity if they arerepeatedly recharged after being only partially discharged—and lowself-discharge. Unfortunately, unlike many non-Li conventional batterychemistries, Li ion batteries can, due to the highly reactive nature ofelemental and ionic Li, present a safety hazard. Li batteries candeteriorate unexpectedly, including through explosions and fires, uponpuncture, abrasive contact, or even excessively charged. In spite ofsuch drawbacks, the high energy density of Li ion batteries remainsattractive as it permits for longer usable lifespans of several hoursbetween charging cycles as well as longer cycle life, referring to theelectric current delivery or output performance of a given Li-ionbattery over multiple repeat charge-discharge, such as partial or totalcharge depletion, cycles.

Overall, Li metal, due to its high theoretical specific capacity of3,860 mAh/g, low density (0.59 g cm−3) and low negative electrochemicalpotential, such as −3.040 V compared to a standard hydrogen electrode,still appears as an ideal material for the negative electrode ofsecondary Li-ion batteries. But, problems continue to persist, such asdendrite growth, referring the growth of a branching tree-like structurewithin the battery itself, which can be caused by Li precipitates.Dendrites, upon growing from one electrode to contact the other, cancause serious safety concerns related to short-circuits, and limitedCoulombic efficiency, discussing to the charge efficiency by whichelectrons are transferred in batteries during deposition and strippingoperations inherent in Li-ion batteries. Such challenges have previouslyimpeded Li ion battery applications.

Concerns related to safety of earlier-developed Li secondary batterieshave led to the development and refinement of current generation Li-ionsecondary batteries. Such Li-ion batteries typically featurecarbonaceous materials used as an anode, such carbonaceous anodematerials including:

graphite;

amorphous carbon; and,

graphitized carbon.

-   The first type of the three carbonaceous materials presented above    includes naturally occurring graphite and synthetic graphite or    artificial graphite, such as Highly Oriented Pyrolytic Graphite,    HOPG. Either form of graphite can be intercalated with Li, such as    that obtained from a molten Li metal source. The resulting Graphite    Intercalation Compound (GIC) may be expressed as Li_(x)C₆, where X    is typically less than 1. To limit or otherwise minimize loss in    energy density due to the replacement of Li metal with the GIC, X in    Li_(x)C₆ must be maximized and the irreversible capacity loss    (Q_(ir)), in the first charge of the battery must be minimized.

As a result, the maximum amount of Li that can be reversiblyintercalated into the interstices between graphene planes of a perfectgraphite crystal is generally believed to occur in a graphiteintercalation compound represented by Li_(x)C₆ (x=1), corresponding to atheoretical 372 mAh/g. However, such a limited specific capacity cannotadequately satisfy the demanding requirements of higher energy-densitypower needs of modern electronics and EVs. Accordingly, carbon-basedanodes, such as graphite intercalated with Li, can demonstrate extendedcycle lifespans due to the presence of a surface-electrolyte interfacelayer (SEI), which results from the reaction between Li and surroundingelectrolyte, or between Li and the anode surface/edge atoms orfunctional groups, during the initial several charge-discharge cycles.Li ions consumed in this reaction, referring to the formation of theSEI, may be derived from some of the Li ions originally intended forcharge transfer, referring to a process of the dissociation of elementalLi when intercalated with carbon in a carbon-based structure, such aswithin the anode.

Charge transfer can occur during Li ion movement in electrolyte across aporous separator to the cathode as related to electron release andtransport to facilitate electric current conduction to power a loadduring typical Li ion battery discharge cycles. During repeated Li ionbattery charge-discharge cycles, the SEI is formed and some of the Liions migrating through the electrolyte become part of the inert SEIlayer and are described as becoming “irreversible”, in that they can nolonger be an active element or ion used for charge transfer. As aresult, it is desirable to minimize the amount of Li used for theformation of an effective SEI layer. In addition to SEI formation,Q_(ir), has been attributed to graphite exfoliation caused byelectrolyte/solvent co-intercalation and other side reactions.

Next, amorphous carbon contains no, or very little, micro- ornano-crystallites and can include both “soft carbon” and “hard carbon”.Soft carbon refers to a carbon material that can be graphitized at atemperature of about 2,500° C. or higher. In contrast, hard carbonrefers to a carbon material that cannot be graphitized at a temperaturehigher than 2,500° C.

In practice and industry, the so-called “amorphous carbons” commonlyused as anode active materials may not be purely amorphous, but rathercontain some minute amount of micro- or nano-crystallites, eachcrystallite being defined as a small number of graphene sheets orientedas basal planes that are stacked and bonded together by weak van derWaals forces. The number of graphene sheets can vary between one andseveral hundreds, giving rise to a c-directional dimension, such asthickness L_(e), of typically 0.34 nm to 100 nm. The length or width(L_(a)) of these crystallites is typically between tens of nanometers tomicrons. Among this class of carbon materials, soft and hard carbons canbe produced by low-temperature pyrolysis (550-1,000° C.) and exhibit areversible specific capacity of 400-800 mAh/g in the 0-2.5 V range. Aso-called “house-of-cards” carbonaceous material has been produced withenhanced specific capacities approaching 700 mAh/g.

Research groups have obtained enhanced specific capacities of up to 700mAh/g by milling graphite, coke, or carbon fibers and have explained theorigin of the additional specific capacity with the assumption that indisordered carbon containing some dispersed graphene sheets, referred toas “house-of-cards” materials, Li ions are adsorbed on two sides of asingle graphene sheet. It has been also proposed that Li readily bondsto a proton-passivated carbon, resulting in a series of edge-oriented Lito C—H bonds. This can provide an additional source of Li+ in somedisordered carbons. Other research suggested the formation of Li metalmonolayers on the outer graphene sheets of graphite nano-crystallites.The discussed amorphous carbons were prepared by pyrolyzing epoxy resinsand may be referred to as polymeric carbons. Polymeric carbon-basedanode materials have also been studied.

Chemistry, performance, cost, and safety characteristics may vary acrossLi ion battery variants. Handheld electronics may use Li polymerbatteries using a polymer gel as electrolyte with Li cobalt oxide(LiCoO₂) as cathode material. Such a configuration can offer relativelyhigh energy density but may present safety risks, especially whendamaged. Li iron phosphate (LiFePO₄), Li ion manganese oxide battery(LiMn₂O₄, Li₂MnO₃, or LMO), and Li nickel manganese cobalt oxide(LiNiMnCoO₂ or NMC) all offer lower energy density yet provide longeruseful lives and less likelihood of fire or explosion. Thus, suchbatteries are widely used for electric tools, medical equipment, andother roles. NMC in particular is often considered for automotiveapplications.

Lithium (Li)—Sulfur (S) Batteries

The lithium-sulfur battery, referred to herein as a Li—S battery, is atype of rechargeable battery, notable for its high specific energy. Therelatively low atomic weight of Li and moderate atomic weight of Sresults in Li—S batteries being relatively light, at about the densityof water).

Li—S batteries may succeed lithium-ion cells because of their higherenergy density and reduced cost due to the use of sulfur. Li—S batteriescan offer specific energies at approximately 500 Wh/kg, which issignificantly better than many conventional Li-ion batteries, which aretypically in the range of 150-250 Wh/kg. Li—S batteries with up to 1,500charge and discharge cycles have been demonstrated. Although presentingmany advantages, a key faced by the Li—S battery is the polysulfide“shuttle” effect that results in progressive leakage of active materialfrom the cathode resulting in an overall low life cycle of the battery.And, the extremely low electrical conductivity of a sulfur cathoderequires an extra mass for a conducting agent to exploit the wholecontribution of active mass to the capacity. Large volumetric expansionof S cathode from elemental S to Li₂S and a large amount of electrolyteneeded are also problem areas demanding attention.

Chemical processes in the Li—S cell include Li dissolution from theanode surface and incorporation into alkali metal polysulfide saltsduring discharge, and reverse lithium plating to the anode whilecharging. At the anodic surface, dissolution of the metallic lithiumoccurs, with the production of electrons and lithium ions during thedischarge and electrodeposition during the charge. The half-reaction isexpressed as:

Li ⇄Li⁺+e⁻  (Eq. 1)

Similar to that observed in Li ion batteries, dissolution and/orelectrodeposition reactions can cause, over time, problems of unstablegrowth of the solid-electrolyte interface (SEI), generating active sitesfor the nucleation and dendritic growth of Li. Dendritic growth isresponsible for the internal short circuit in Li batteries and leads tothe death of the battery itself.

In Li—S batteries, energy is stored in the sulfur electrode (S₈), whichis the cathode. During cell discharge cycles, Li ions in the electrolytemigrate from the anode to the cathode where the S is reduced to lithiumsulphide (Li₂S). The sulfur is reoxidized to S₈ during the refillingphase. The semi-reaction is expressed at a high level of abstraction,for explanatory purposes, as:

S+2Li⁺+2e⁻⇄Li₂S(E°≈2.15 V vs Li/Li+)  (Eq. 2)

In reality, the S reduction reaction to Li₂S is significantly morecomplex and involves the formation of several Li polysulphides(Li₂S_(x), 8<x21 1) at decreasing chain length according to the order:

Li₂S₈→Li₂S₆→Li₂S₄→Li₂S₂→Li₂S  (Eq. 3)

The final product is a mixture of Li₂S₂ and Li₂S rather than just pureLi₂S, due to the slow reduction kinetics at Li₂S. This is in contrastwith conventional Li ion cells, where the Li ions are intercalated inboth of the anode and the cathode. For example, in Li S battery systems,each S atom can host two Li ions. Typically, Li ion batteries canaccommodate only 0.5-0.7 lithium ions per host atom. As a result, Li—Sallows for a much higher Li storage density. Polysulfides (PS) arereduced on the cathode surface in sequence while the cell isdischarging:

S₈→Li₂S₈→Li₂S₆→Li₂S₄→Li₂S₃  (Eq. 4)

Across a porous diffusion separator, S polymers form at the cathode asthe cell charges:

Li₂S→Li₂S₂→Li₂S₃→Li₂S₄→Li₂S₆→Li₂S₈→S₈  (Eq. 5)

-   These reactions can analogous to those in the sodium (Na)—S battery.

Primary challenges concerning Li—S battery systems include the lowrelatively low conductivity of S, its massive volume change upondischarging, and finding a suitable cathode, such as that constructedfrom any of the presently disclosed carbon-based structures, is thefirst step for commercialization of Li—S batteries. Currently,conventional Li S batteries use a carbon/sulfur cathode and a Li anode.Sulfur is naturally abundant and relatively low cost, but haspractically no electroconductivity, 5×10⁻³⁰ S·cm−1 at 25° C. A carboncoating provides the missing electroconductivity. Carbon nanofibersprovide an effective electron conduction path and structural integrity,at the disadvantage of higher cost.

One problem with the Li—S design is that when the S in the cathodeabsorbs Li, volume expansion of the Li_(x)S compositions takes place,and predicted volume expansion of Li₂S is nearly 80% of the volume ofthe original S. This causes large mechanical stresses on the cathode,which is a major cause of rapid degradation. Such process reduces thecontact between the carbon (C), the S and prevents the flow of Li ionsto the carbon surface.

Mechanical properties of the lithiated S compounds are stronglycontingent on the Li content, and with increasing Li content, thestrength of lithiated S compounds improves, although this increment isnot linear with Li. One of the primary shortfalls of most Li—S cellsconcerns unwanted reactions with the electrolyte. While S and Li₂S arerelatively insoluble in most electrolytes, many intermediatepolysulfides (PS) are not such that dissolving Li₂S_(n) into theelectrolyte can cause irreversible loss of active S. Use of highlyreactive Li as a negative electrode causes dissociation of most of thecommonly used other type electrolytes. Use of a protective layer in theanode surface has been studied to improve cell safety, such as usingTeflon coating showed improvement in the electrolyte stability, LIPON,Li₃N also exhibited promising performance.

The “shuttle” effect has been observed to be the primary cause ofdegradation in a Li—S battery. The Li PS Li₂S_(x) (6≤x≤8) is highlysoluble in the common electrolytes used for Li—S batteries. They areformed and leaked from the cathode and they diffuse to the anode, wherethey are reduced to short-chain PS and diffuse back to the cathode wherelong-chain PS is formed again. This process results in the continuousleakage of active material from the cathode, lithium corrosion, lowcoulombic efficiency, and low battery life due to batteryself-discharge. Moreover, the “shuttle” effect is responsible for thecharacteristic self-discharge of Li—S batteries, because of slowdissolution of PS, which occurs also in rest state. The “shuttle” effectin Li—S battery can be quantified by a factor f_(c) (0<f_(c<)1),evaluated by the extension of the charge voltage plateau. The factor fcis given by the expression:

$\begin{matrix}{{fc} = \frac{k_{s}{q_{up}\left\lbrack S_{tot} \right\rbrack}}{I_{c}}} & \left( {{Eq}.\mspace{14mu} 6} \right)\end{matrix}$

where k_(s), q_(up), [S_(tot)] and I_(c) are respectively the kineticconstant, specific capacity contributing to the anodic plateau, thetotal sulfur concentration and charge current.

Electrical Conductance of Carbon-Based Materials

Advances in high conductance carbon materials such as carbon nanotubes(CNT), graphene, amorphous carbon, and/or crystalline graphite inelectronics allows for the printing of these materials onto many typesof surfaces without requiring usage of printed circuit boards, andwithout the use of materials or compounds that have been identified asbeing toxic to humans. Usage of high conductance carbon as a feedstockmaterial or other material during any one or more of the additivemanufacturing processes described above may facilitate the fabricationof batteries with micro-lattice structures suitable for enhancedfunctionality, electric power storage and delivery, and optimalefficiency. Although many of the devices described may serve as powersources such as batteries or capacitors, those of skill in the art willappreciate that printing technologies, such as 3D printing, may beconfigured using high conductance carbon materials such as carbonnanotubes (CNT), graphene, amorphous carbon, or crystalline graphite toform other electronic devices.

Printing technologies using high conductance carbon materials such ascarbon nanotubes (CNT), graphene, amorphous carbon, or crystallinegraphite may be implemented and/or otherwise incorporated in thefabrication of the following devices: antennas, tuned antennas, sensors,bio-sensors, energy harvesters, photocells, and other electronicdevices.

Graphene

Graphene is an allotrope of carbon in the form of a single layer ofatoms in a two-dimensional hexagonal lattice in which one atom formseach vertex. It is the basic structural element of other allotropes,including graphite, charcoal, carbon nanotubes and fullerenes. It canalso be considered as an indefinitely large aromatic molecule, theultimate case of the family of flat polycyclic aromatic hydrocarbons.

Graphene has a special set of properties which set it apart from otherelements. In proportion to its thickness, it is about 100 times strongerthan the strongest steel. Yet its density is dramatically lower than anyother steel, with a surfacic, such as surface-related, mass of 0.763 mgper square meter. It conducts heat and electricity very efficiently andis nearly transparent. Graphene also shows a large and nonlineardiamagnetism, even greater than graphite and can be levitated by Nd—Fe—Bmagnets. Researchers have identified the bipolar transistor effect,ballistic transport of charges and large quantum oscillations in thematerial. Its end-use application areas are widespread, finding uniqueimplementations in advanced materials and composites, as well as beingused as a formative material to construct ornate scaffolds usable in Liion battery electrodes to enhance ion transport and electric currentconduction to yield specific capacity and power delivery figures nototherwise attainable by conventional battery technologies.

Chemical Functionalization of Graphene

Functionalization implies the process of adding new functions, features,capabilities, or properties to a material or substance by altering thesurface chemistry of the material. Functionalization is used throughoutchemistry, materials science, biological engineering, textileengineering, and nanotechnology and may be performed by attachingmolecules or nanoparticles to the surface of a material, with a chemicalbond or through adsorption, the adhesion of atoms, ions or moleculesfrom a gas, liquid or dissolved solid to a surface to create a film ofthe adsorbate on the surface of the adsorbent without forming a covalentor ionic bond thereto.

Functionalization and dispersion of graphene sheets may be of criticalimportance to their respective end-use applications. Chemicalfunctionalization of graphene enables the material to be processed bysolvent-assisted techniques, such as layer-by-layer assembly,spin-coating, and filtration and also prevents the agglomeration ofsingle layer graphene (SLG) during reduction and maintains the inherentproperties of graphene.

Currently, the functionalization of graphene may be performed bycovalent and noncovalent modification techniques. In both instances,surface modification of graphene oxide followed by reduction has beencarried out to obtain functionalized graphene. It has been found thatboth the covalent and noncovalent modification techniques are veryeffective in the preparation of processable graphene.

However, electrical conductivity of functionalized graphene has beenobserved to decrease significantly compared to pure graphene. Moreover,the surface area of the functionalized graphene prepared by covalent andnon-covalent techniques decreases significantly due to the destructivechemical oxidation of flake graphite followed by sonication,functionalization, and chemical reduction. To overcome these problems,studies have been reported on the preparation of functionalized graphenedirectly from graphite in a one-step process. In all these cases,surface modification of graphene can prevent agglomeration andfacilitates the formation of stable dispersions. Surface modifiedgraphene can be used for the fabrication of polymer nanocomposites, Liion battery electrodes, super-capacitor devices, drug delivery system,solar cells, memory devices, transistor device, biosensor, etc.

Graphite

Graphite, as commonly understood and as referred to herein, implies acrystalline form of elemental carbon with atoms arranged in a hexagonalstructure. Graphite occurs naturally in this form and is the most stableform of carbon under standard, such as atmospheric, conditions.Otherwise, under high pressures and temperatures, graphite converts todiamond. Graphite is used in pencils and lubricants. Its highconductivity makes it useful in electronic products such as electrodes,batteries, and solar panels.

Roll-to-Roll (R2R) Processing

R2R processing refers to the process of creating electronic devices on aroll of flexible plastic or metal foil. R2R processing may also refer toany process of applying coatings, printing, or performing otherprocesses starting with a roll of a flexible material and re-reelingafter the process to create an output roll. These processes, and otherssuch as sheeting, may be grouped together under the general term“converting”. When the rolls of material have been coated, laminated, orprinted they can be subsequently cut and/or slit to their finished sizeon a slitter rewinder.

R2R processing of large-area electronic devices may reduce manufacturingcost. Other applications could arise which take advantage of theflexible nature of the substrates, such as electronics embedded intoclothing, 3D-printed Li ion batteries, large-area flexible displays, androll-up portable displays.

Oxidation-Reduction (Redox) Reactions

Redox are a type of chemical reaction in which the oxidation states ofatoms are changed. Redox reactions are characterized by the transfer ofelectrons between chemical species, most often with one species, thereducing agent, undergoing oxidation by losing electrons while anotherspecies, such as the oxidizing agent, undergoes reduction by gainselectrons. The chemical species from which the electron is stripped issaid to have been oxidized, while the chemical species to which theelectron is added is said to have been reduced.

Intercalation

Intercalation implies the reversible inclusion or insertion of amolecule, or ion, into materials with layered structures. Examples arefound in graphite, graphene, and transition metal dichalcogenides.

Li Intercalation into Bi- or Multi-Layer Graphene

Electrical storage capacity of graphene and the Li-storage process ingraphite currently present challenges requiring further development inthe field of Li ion batteries. Efforts have therefore been undertaken tofurther develop three-dimensional bi-layer graphene foam with fewdefects and a predominant Bernal stacking configuration, a type ofbilayer graphene where half of the atoms lie directly over the center ofa hexagon in the lower graphene sheet, and half of the atoms lie over anatom, and to investigate its Li-storage capacity, process, kinetics, andresistances. Li atoms may be stored only in the graphene interlayer.Further, various physiochemical characterizations of the staged Libilayer graphene products further reveal the regular Li-intercalationphenomena and illustrate this Li storage pattern of two-dimensions.

Electrochemical Capacitors (ECs)

Electrochemical capacitors (ECs), also referred to as ultracapacitors orsupercapacitors, are being considered for uses in hybrid or full EVs.ECs can supplement, or in certain uses replace, traditional batteries,including high-performance Li ion batteries, used in an EVs to provideshort bursts of power, such as that needed for forward propulsion, oftenneeded for rapid acceleration. Traditional batteries may still be usedprovide uniform power for cruising at normal highway speeds, butsupercapacitors, with their ability to release energy much more quicklythan batteries, may activate and supplement battery-provided power atspecific times, such as when a so-equipped car needs to accelerate, suchas for merging, passing, emergency maneuvers, and hill climbing.

ECs must also store sufficient energy to provide an acceptable drivingrange, such as from 220-325 miles or more. And, to be cost- andweight-effective relative to additional battery capacity, ECs mustcombine adequate specific energy and specific power with long cycle lifeand meet cost targets as well. Specifically, ECs for application in EVsmust store about 400 Wh of energy, be able to deliver about 40 kW ofpower for about 10 seconds and provide high cycle-life, such as >100,000cycles.

The high volumetric capacitance density of an EC, such as 10 to 100times greater than conventional capacitors, derives from using porouselectrodes, which may incorporate, feature, and/or be constructed fromscaffolded graphene-based materials, to create a large effective “platearea” and from storing energy in the diffuse double layer. This doublelayer, created naturally at a solid-electrolyte interface when voltageis imposed, has a thickness of only about 1-2 nm, therefore forming anextremely small effective “plate separation.” In some ECs, stored energyis further augmented by pseudo-capacitance effects, occurring again atthe solid-electrolyte interface due to electrochemical phenomena such asthe redox charge transfer. The double layer capacitor is based on a highsurface area electrode material, such as activated carbon, immersed inan electrolyte. A polarized double layer is formed atelectrode-electrolyte interfaces providing high capacitance.

Overview Introduction

Technological advances concerning modern carbon-based materials such asgraphene have, in turn, enhanced applications of such materials in manyend-use areas, such as in advanced secondary batteries. Such batteriescan employ electrochemical Li intercalation or de-intercalation to takeadvantage of favorable properties of carbon and carbon-based materials,which can depend significantly on their respective morphology,crystallinity, orientation of crystallites, and defects as well. Forinstance, the electric storage capacity of a Li-ion battery can beenhanced by the selection and integration of desirable nano-structuredcarbon materials such as carbon in certain allotropes such as graphiteand graphene, or nano-sized graphite, nanofibers, isolated single walledcarbon nanotubes, nano-balls, and nano-sized amorphous carbon, eachhaving small carbon nanostructures in which no dimension is greater thanabout 2 μm.

Known methods for fabricating carbon and Li-ion electrodes forrechargeable Li cells include steps for forming a carbon electrode. Sucha carbon electrode can be composed of graphitic carbon particles adheredto each other by an ethylene propylene diene monomer binder used toachieve a carbon electrode capable of subsequent intercalation byLi-ions. The carbon electrode is then reacted with infiltrated lithium(Li) metal to incorporate Li-ions obtained therefrom into graphiticcarbon particles of the electrode. A voltage can be repeatedly appliedto the carbon electrode to initially cause a surface reaction betweenthe Li-ions and to the carbon and subsequently cause intercalation ofthe Li-ions into crystalline layers of the graphitic carbon particles.With repeated application of the voltage, intercalation can be achievedto near a theoretical maximum and assist in the conduction of electricalcurrent as may be desirable.

Other exfoliated graphite-based hybrid material compositions relate to:

-   -   micron- or nanometer-scaled particles or coating which are        capable of absorbing and desorbing alkali or alkaline metal        ions, particularly, Li ions; and,    -   exfoliated graphite flakes that are substantially interconnected        to form a porous, conductive graphite network including pores        defined therein.

-   The particles or coating resides in a pore of the network or is    attached to a flake of the network. The exfoliated graphite amount    is in the range of 5% to 90% by weight and the number of particles    or amount of coating is in the range of 95% to 10% by weight.

Also, high capacity silicon-based anode active materials have been shownto be effective in combination with high capacity Li rich cathode activematerials. Supplemental Li is shown to improve the cycling performanceand reduce irreversible capacity loss for some silicon based activematerials. Silicon based active materials can be formed in compositeswith electrically conductive coatings, such as pyrolytic carbon coatingsor metal coatings, and composites can also be formed with otherelectrically conductive carbon components, such as carbon nano fibersand carbon nanoparticles.

And, known rechargeable batteries of an alkali metal having an organicelectrolyte experiences little capacity loss upon intercalation of thecarbonaceous electrode with the alkali metal. The carbonaceous electrodemay include a multi-phase composition including both highly graphitizedand less graphitized phases or may include a single phase, highlygraphitized composition subjected to intercalation of Li at above about50° C. Incorporation of an electrically conductive filamentary materialsuch as carbon black intimately interspersed with the carbonaceouscomposition minimizes capacity loss upon repeated cycling.

Otherwise, a known Li based anode material can be characterized byincluding 1 m²/g or more of carbonaceous anode active material specificsurface area, a styrene-butadiene rubber binder, and a fiber diameterformed to 1,000 nanometers of carbon fiber. Such anode materials areused for Li batteries, which have desirable characteristics, such as alow electrode resistance, high strength of the electrode, anelectrolytic solution having excellent permeability, high energy densityand a high rate charge/discharge. The negative electrode materialcontains 0.05 to 20 mass % of carbon fibers and a styrene at 0.1 to 6.0%by mass. Butadiene rubber forms the binder and may further contain 0.3to 3% by mass thickener, such as carboxymethyl methylcellulose.

Existing technologies have been shown that relate to a battery that hasan anode active material that has been:

-   -   pre-lithiated; and,    -   pre-pulverized.

-   Such an anode may be prepared with a method that comprises:    -   providing an anode active material;    -   intercalating or absorbing a desired amount of Li into the anode        active material to produce a pre-lithiated anode active        material;    -   comminuting, referring to the reduction of solid materials from        one average particle size to a smaller average particle size, by        crushing, grinding, cutting, vibrating, or other processes, the        pre-lithiated anode active material into fine particles with an        average size less than 10 μm, preferably <1 μm and most        preferably <200 nm; and,    -   combining multiple fine particles of the pre-lithiated anode        active material with a conductive additive and/or a binder        material to form the anode.

-   The pre-lithiated particles are protected by a Li ion-conducting    matrix or coating material. The matrix material is reinforced with    nano graphene platelets.

Graphitic nanofibers have also been disclosed and include tubularfullerenes, commonly called “buckytubes”, nano tubes and fibrils, whichare functionalized by chemical substitution, are used as electrodes inelectrochemical capacitors. The graphitic nanofiber-based electrodeincreases the performance of the electrochemical capacitors. Preferrednanofibers have a surface area greater than about 200 m²/gm and aresubstantially free of micropores.

And, known high surface area carbon nanofibers have an outer surface onwhich a porous high surface area layer is formed. Methods of making thehigh surface area carbon nanofiber include pyrolizing a polymericcoating substance provided on the outer surface of the carbon nanofiberat a temperature below the temperature at which the polymeric coatingsubstance melts. The polymeric coating substance used as the highsurface area around the carbon nanofiber may include phenolics such asformaldehyde, polyacrylonitrile, styrene, divinyl benzene, cellulosicpolymers and cyclotrimerized diethynyl benzene. The high surface areapolymer which covers the carbon nanofiber may be functionalized with oneor more functional groups.

Synthesis of the Presently Disclosed Carbons

As presented above, conventional Li-intercalated carbon-basedcompositions or compounds may include traditional battery electrodematerials such as:

-   -   graphene or multi-layer 3D graphene particles;    -   electrically conductive carbon particles; and,    -   binder, such as that provided as a fluid, such as a liquid, form        and/or in particulate form, configured to retain carbon-based        particle in their respective desired positions and to provide        overall structural integrity to carbon-based systems.

In conventional techniques, particles are all typically deposited, suchas being dropped into, existing slurry cast electrodes including currentcollectors made from metal foil such as copper. Slurry typically isprepared to contain an organic binder or binder material referred to asNMP, an organic compound consisting of a 5-membered lactam, used in thepetrochemical and plastics industries as a solvent, exploiting itsnonvolatility and ability to dissolve diverse materials. The ratio ofactive materials to conductive carbon or carbon-based particles isusually at 5 parts of conductive carbon to a predominant balance ofactive material with a nominal quantity of binder or binding material,such as NMP, included as well. The relative amounts of binder andconductive phases of carbon may be dictated by creating an electricallyconductive path or paths between larger particles of those mentioned.

Regarding difficulties related to binder implementation and usage insecondary batteries, studies have shown that developing high-performancebattery systems requires the optimization of every battery component,from electrodes and electrolyte to binder systems. However, theconventional strategy to fabricate battery electrodes by casting amixture of active materials, a nonconductive polymer binder, and aconductive additive onto a metal foil current collector usually leads toelectronic or ionic bottlenecks and poor contacts due to the randomlydistributed conductive phases, which can be an issue that can beobserved in either the anode or the cathode. And, when high-capacityelectrode materials are employed, the high stress generated duringelectrochemical reactions can disrupt the mechanical integrity oftraditional binder systems, resulting in decreased cycle life ofbatteries. Thus, there is a critical need to design novel and robustbinder systems, or scaffolded carbon-based electrode structures thatdemonstrate structural integrity absent of usage of a binder, that canprovide reliable, low-resistance, and continuous internal voids,micropores, and pathways to retain active material when and wheredesirable during battery charge-discharge cycles, and to connect allregions of the electrode.

In contrast to that traditionally done, and to address shortcomings ofbinder performance related to decreased cycle life of batteries, thepresently disclosed inventive compositions of matter and methods orprocesses for the production thereof can eliminate:

-   -   any and all forms of a binder phase; and,    -   potentially certain regions, features and/or aspects of a        conductive phase defined by larger carbon-based particles, such        as those including graphite, and/or forms of graphene extracted        or otherwise created from the exfoliation of graphite.

This is done by fabricating a particle where interconnected 3Dagglomerations of multiple layers of graphene sheets fuse or sintertogether, such as randomly, or with controlled directionality such asorthogonally, or otherwise adjoin together to serve as a type ofintrinsic, self-supporting, “binder” or joining material that serves asa binder replacement, effectively allowing for the elimination of aseparate traditional binder material to achieve substantial weightreduction. Such a format also permits for the elimination of a separateand dedicated current collector, which is typically a required componentof many batteries. Elimination of the binder phase and/or the currentcollector, provide for beneficial and desirable features, such as:

-   -   having low per-unit production cost allowing for        mass-producibility,    -   high reversible specific capacity,    -   low irreversible capacity,    -   small particle sizes, such as permitting for high        throughput/rate capacity,    -   compatibility with commonly used electrolytes for convenient        integration and usage in commercial battery applications, and    -   long charge-discharge cycle life for consumer benefit, across        any number of demanding end-use applications, including        automobiles, airplanes, and spacecraft.

Notably, techniques disclosed herein yield unexpected favorable results.They do not require traditional processes to create graphene sheets suchas from the exfoliation of graphite, and instead synthesize one or morea multi-modal carbon-based s from an atmospheric plasma-based vapor flowstream. Synthesis of carbon-based particles can occur either in-flightto nucleate from an initially formed carbon-based homogenous nucleationor during deposition directly onto a supporting or sacrificialsubstrate. Therefore, any one or more of the presently disclosedtechniques permit for the growth of ornate carbon-based structuresindependent of a traditionally required seed particle upon whichnucleation occurs.

In conventional techniques, the production of functional graphene reliesupon usage of graphite as a starting material. Graphite, being aconductive material, has been used as an electrode in batteries andother electrochemical devices. In addition to its function as an inertelectrode, electrochemical methods have been employed to form graphiteintercalation compounds (GICs) and, more recently, to exfoliate graphiteinto few-layered graphene. Exfoliation, as generally understood and asreferred to herein, implies—in an intercalation chemistry relatedcontext—the complete separation of layers of material, and typicallyrequires aggressive conditions involving highly polar solvents andaggressive reagents. Electrochemical methods are attractive as theyeliminate the use of chemical oxidants as the driving force forintercalation or exfoliation, and an electromotive force is controllablefor tunable GICs. More importantly, the extensive capabilities ofelectrochemical functionalization and modification enable the facilesynthesis of functional graphene and its value-added nanohybrids.

Unlike exfoliation, inclusive of the thermal exfoliation of graphite toproduce graphene, the presently disclosed methods relate to one or morecarbon-inclusive gaseous species, such as those including methane (CH₄),being flowed into a reaction chamber of a microwave-based or thermalreactor. Upon receipt of energy, such as that provided byelectromagnetic radiation and/or thermal energy, incoming gaseousspecies spontaneously crack to form allotropes with other crackedcarbons from additional gaseous species supplied into the reactor tocreate an initial carbon-based site such as a formed particle, whicheither has or otherwise facilitates:

-   -   additional particles that grow or nucleate off of defects from        that initial formed particle; or,    -   orthogonally fuse or sinter additional carbon-based particles,        where there is sufficient local energy at the collision spot for        the colliding particles to combine.

System Structure Carbon-Based Particles—in Detail

FIG. 1A shows a carbon-based particle 100A having controllableelectrical and ionic conducting gradients therein, within which variousaspects of the subject matter disclosed herein may be implemented. Thecarbon-based particle 100A can be synthesized through self-assemblyindependent of a binder to feature multi-modal dimensions, includingvarious orifices, conduits, voids, pathways, conduits or the like, anyone or more defined to have a specific dimension, such as beingmesoporous. A mesoporous material implies a material containing poreswith diameters between 2 and 50 nm, according to IUPAC nomenclature. Forthe purposes of comparison, IUPAC defines microporous material as amaterial having pores smaller than 2 nm in diameter and macroporousmaterial as a material having pores larger than 50 nm in diameter.

Mesoporous materials may include various types of silica and aluminathat have similarly sized mesopores. Mesoporous oxides of niobium,tantalum, titanium, zirconium, cerium and tin have been researched andreported. Of all the variants of mesoporous materials, mesoporouscarbon, such as carbons and carbon-based materials have voids, orifices,pathways, conduits or the like having at least one mesoporous dimension,has achieved particular prominence, having direct applications in energystorage devices. Mesoporous carbon can be defined as having porositywithin the mesopore range, and this significantly increases the specificsurface area. Another common mesoporous material is activated carbon,referring to a form of carbon processed to have small, low-volume poresthat increase the surface area. Activated carbon, in a mesoporouscontext, is typically composed of a carbon framework with bothmesoporosity and microporosity, such as depending on the conditionsunder which it was synthesized. According to IUPAC, a mesoporousmaterial can be disordered or ordered in a mesostructure. In crystallineinorganic materials, mesoporous structure noticeably limits the numberof lattice units, and this significantly changes the solid-statechemistry. For example, the battery performance of mesoporouselectroactive materials is significantly different from that of theirbulk structure.

The carbon-based particle 100A is nucleated and grown in an atmosphericplasma-based vapor flow stream of reagent gaseous species such asmethane (CH₄) to form an initial carbon-containing and/or carbon-basedparticle without specifically or explicitly requiring a separatestand-alone initial seed particle around which carbon structures aresubsequently grown, as seen in conventional techniques. An initialcarbon-based synthesized particle independent of a separate seedparticle pursuant to the presently disclosed embodiments can then beexpanded:

-   -   in-flight, describing the systematic coalescence pursuant to        nucleation and/or growth from an initial carbon-based homogenous        nucleation independent of a seed particle of additional        carbon-based material derived from incoming carbon-containing        gas mid-air within a microwave-plasma reaction chamber; or,    -   by being grown and/or deposited directly onto a supporting or        sacrificial substrate, such as a current collector, within a        thermal reactor.

-   Coalescence implies a process in which two phase domains of the same    composition come together and form a larger phase domain.    Alternatively put, the process by which two or more separate masses    of miscible substances seem to pull each other together should they    make the slightest contact. The carbon-based particle 100A, may be    alternatively referred to as just particle, and/or by any other    similar term. The term mesoporous, as both generally understood and    as used herein, may be defined as a material containing pores with    diameters between 2 and 50 nm, according to International Union of    Pure and Applied Chemistry (IUPAC) nomenclature.

Synthesis and/or growth of carbon-based particle 100A within a reactionchamber in and/or otherwise associated with a microwave-based reactor,such as a reactor is disclosed by Stowell, et al., “Microwave ChemicalProcessing Reactor”, U.S. Pat. No. 9,767,992, filed on Sep. 19, 2017,incorporated by reference herein in its entirety. Synthesis can occur insystems other than microwave reactors such as taking place in a thermalreactor, referring generally to a chemical reactor defined by anenclosed volume in which a temperature-dependent chemical reactoroccurs.

The carbon-based particle 100A, also shown as a carbon-based particle100D in FIG. 1D, is synthesized as so described herein with athree-dimensional (3D) hierarchical structure comprising short range,local nano-structuring in combination with long range approximatefractal feature structuring, which in this context refers to theformation of successive layers positioned orthogonally to each other.Orthogonally here is defined as involving the 90-degree rotation of eachsuccessive layer relative to the one beneath it, and so on and so forth,allowing for the creation of vertical, or substantially vertical, layersand/or intermediate layers.

Contiguous microstructures 107E suitable for incorporation within anelectrochemical cell cathode for lithium-sulfur (Li S) secondary systemsare shown in FIG. 1E, which itself shows an enlarged and more detailedview of the hierarchical pores 101A shown in FIGS. 1A and 1D. In someimplementations, contours and shapes of the contiguous microstructures107E can structurally define the open porous scaffold 102A, as shown inFIG. 1A, with diffusion pathways 109E, which are suitable for Li iontransport from the anode to the cathode during discharge-charge cycles.The contiguous microstructures 107E can include:

-   -   microporous frameworks, such as the diffusion pathways 109E,        defined by a dimension 101E of >50 nm that provide tunable Li        ion conduits;    -   mesoporous channels defined by a dimension 102E of about 20 nm        to about 50 nm (generally defined under IUPAC nomenclature and        referred to as mesopores or mesoporous) that act as Li        ion-highways for rapid Li ion transport therein; and    -   microporous textures, such as pores 105E, defined by a dimension        103E of <4 nm for charge accommodation and/or active material,        such as sulfur (S) in Li S systems, confinement.

A hierarchical porous network 100E including the diffusion pathways109E, in addition to providing pores 105E for confining active materialand defining pathways for ion transport, can be configured to define thecontiguous microstructures 107E for providing active Li intercalatingstructures. Accordingly, the hierarchical porous network 100E of thecarbon-based particle 100D can be implemented in either an anode or acathode or, for example, a Li ion or a Li S battery system with aspecific capacity rated at between about 744 mAh/g to about 1,116 mAh/g.For either Li ion or Li S configurations, Li can infiltrate open porousscaffold, such as when provided by molten Li metal via capillaryinfusion, to at least partially chemically react with exposed carbontherein in reactive systems.

One or more physical, electrical, chemical and/or material properties ofthe carbon-based particle 100A may be defined during its synthesis.Also, dopants, referring to traces of impurity element that isintroduced into a chemical material to alter its original electrical oroptical properties, such as Si, SiO, SiO2, Ti, TiO, Sn, Zn, and/or thelike. may be dynamically incorporated during synthesis of thecarbon-based particle 100A to at least in part affect materialproperties including electrical conductivity, wettability, and/or ionconduction or transport through the hierarchical porous network 100E.Microporous textures having dimension 103E and/or hierarchical porousnetwork 100E more generally may be synthesized, prepared, or created toinclude smaller pores for chemical, such as sulfur (S),micro-confinement, the smaller pores being defined as ranging from 1 to3 nm. Also, each graphene sheet, such as shown in FIG. 1C, may rangefrom 50 to 200 nm in diameter (L_(a)).

The open porous scaffold 102A may be synthesized independent of abinder, such as a traditional, nonconductive polymer binder typicallyused in conjunction with and a conductive additive onto a metal foilcurrent collector in battery end-use applications. Traditionalconfigurations involving usage of a binder can lead toelectronic/current conduction-related or ionic constrictions and poorcontacts due to randomly distributed conductive phases. Moreover, whenhigh-capacity electrode materials are employed, relatively high physicalstress generated during electrochemical reactions can disrupt mechanicalintegrity of traditional binder systems, therefore, in turn, reducingcycle life of batteries.

A vapor flow stream used to synthesize the carbon-based particle 100A,or the carbon-based particle 100D, which is or can be identical to thecarbon-based particle 100A, may be at least flowed in part into avicinity of a plasma, such as that generated and/or flowed into areactor and/or chemical reaction vessel. Such a plasma reactor may beconfigured to propagate microwave energy toward the vapor flow stream toat least in part assist with synthesis of carbon-based particle 100A,may involve carbon-particle based and/or derived nucleation and growthfrom constituent carbon-based gaseous species, such as methane (CH₄),where such nucleation and growth may substantially occur from aninitially formed carbon-based homogenous nucleation independent of aseed particle within a reactor. Such a reactor accommodates control ofgas-solid reactions under non-equilibrium conditions, where thegas-solid reactions may be controlled at least in part by any one ormore of:

-   -   ionization potentials and/or thermal energy associated with        constituent carbon-based gaseous species introduced to the        reactor for synthesis of the carbon-based particle; and/or    -   kinetic momentum associated with the gas-solid reactions.

-   The vapor flow stream may be flowed into a reactor and/or reaction    chamber for the synthesis of carbon-based particle 100A at    substantially atmospheric pressure. And, change in wettability of    carbon-based particle 100A and/or any constituent members such as    open porous scaffold 102A at least in part may involve adjustment of    polarity of a carbon matrix associated with carbon-based particle    100A.

Procedures for Synthesis Microwave Reactor

A vapor flow stream including carbon-containing constituent species,such as methane (CH₄), may be flowed into one of two general reactortypes to produce the carbon-based particle 100A:

-   -   a thermal reactor; or,    -   a microwave-based reactor. Suitable types of microwave reactors        are disclosed by Stowell, et al., “Microwave Chemical Processing        Reactor”, U.S. Pat. No. 9,767,992 filed on Sep. 19, 2017,        incorporated herein by reference in its entirety.

The term in-flight implies a novel method of chemical synthesis based oncontacting particulate material derived from inflowing carbon-containinggaseous species, such as those containing methane (CH₄), to crack suchgaseous species. Cracking, as generally understood and as referred toherein, implies the technical process of methane pyrolysis to yieldelemental carbon, such as high-quality carbon black, and hydrogen gas,without the problematic contamination by carbon monoxide, and withvirtually no carbon dioxide emissions. A basic endothermic reaction thatmay occur within a microwave reactor to create the carbon-based particle100A is shown as equation (7) below:

CH₄+74.85 kJ/mol→C+2H₂  (7)

Carbon derived from the above-described cracking process and/or asimilar or a dissimilar process may fuse together while being dispersedin a gaseous phase, referred to as in-flight, to create carbon-basedparticles, structures, substantially 2D graphene sheets, 3Dagglomerations, and/or pathways defined therein, including:

-   -   interconnected 3D agglomerations 101B of multiple layers of        graphene sheets 101C and/or single layer graphene as        schematically depicted in FIG. 1C, that are fused together to        form the open porous scaffold 102A that facilitates electrical        conduction along and across contact points of the graphene        sheets 101C, which, as shown in FIG. 1B, may include and/or        refer to 5 to 15 layers of few-layer graphene that are oriented        in a stacked configuration to have a vertical height referred to        as a stack height (L_(c)); and,    -   any one or more of the contiguous microstructures 107E        interspersed with or otherwise defined in shape by the        interconnected 3D agglomerations 101B ; in some configurations,        the interconnected 3D agglomerations can be prepared to comprise        one or more of single layer graphene (SLG), few layer graphene        (FLG) defined as ranging from 5 to 15 layers of graphene, or        many layer graphene (MLG).

As introduced earlier, interconnected 3D agglomerations of multiplelayers of graphene sheets 101B orthogonally fused together to serve as atype of intrinsic, self-supporting, binder or joining material allowingfor the elimination of a separate traditional binder material. Suchprocedures are substantially different from conventional sintering, orfrittage, as commonly understood and as referred to herein, whichimplies the process of compacting and forming a solid mass of materialby heat or pressure without melting it to the point of liquefactionwhere materials are bonded at specific acute angles to one-another.

Few layer graphene (FLG), defined herein as ranging from 5 to 15 layersor sheets of graphene, are fused at an angle that is not flat relativeto other FLG sheets to nucleate and/or grow at an angle and thereforeself-assemble over time. Moreover, process conditions may be tuned toachieve synthesis, nucleation, and/or growth of the carbon-basedparticle 100A, also referring to a plurality of carbon-based particles,on a component and/or a wall surface within a reaction chamber, orentirely in-flight upon contact with other carbon-based materials.

Electrical conductivity of deposited carbon and/or carbon-basedmaterials may be tuned by adding metal additions into the carbon phasein the first part of the deposition phase or to vary the ratios of thevarious particles discussed. Other parameters and/or additions may beadjusted, as a part of an energetic deposition process, such that thedegree of energy of deposited carbon and/or carbon-based particles willeither:

-   -   bind together; or,    -   not bind together.

By nucleating and/or growing the carbon-based particle 100A in anatmospheric plasma-based vapor flow stream either in-flight or directlyonto a supporting or sacrificial substrate, a number of the steps andcomponents found in both traditional batteries and traditionalbattery-making processes can be eliminated. Also, a considerable amountof tailoring and tunability can be enabled or otherwise added into thediscussed carbons and/or carbon-based materials.

For instance, a traditional battery may use a starting stock of activematerials, graphite, etc., which may be obtained as off-the-shelfmaterials to be mixed into a slurry. In contrast, the carbon-basedparticle 100A disclosed herein may enable, as a part of the carbon orcarbon-based material synthesis and/or deposition process, tailoringand/or tuning the properties of materials, in real-time, as they arebeing synthesized in-flight and/or deposited onto a substrate. Thiscapability presents a surprising, unexpected, and substantial favorabledeparture from that currently available regarding creation ofcarbon-based scaffolded electrode materials in the secondary batteryfield.

Reactor and/or reactor design of that disclosed by Stowell, et al.,“Microwave Chemical Processing Reactor”, U.S. Pat. No. 9,767,992 filedon Sep. 19, 2017 may be adjusted, configured and/or tailored to controlwanted or unwanted nucleation sites on internal surfaces of reactionchambers exposed to carbon-based gaseous feedstock species, such asmethane (CH₄). In-flight particles qualities may be influenced by theirsolubility in the gaseous species in which they are flowed in such thatonce a certain energy level is achieved, it is not inconceivable forcarbon to crack off, as described by thermal cracking, and form its ownsolid in a microwave reactor.

Adjusting for Unwanted Carbon Accumulation on Reaction Chamber Walls

Moreover, tuning of disclosed reactors and related systems may beperformed to both proactively, such as prior to the observation ofundesirable process conditions, and reactively, such as after suchconditions are observed, address issues associated with carbon-basedmicrowave reactor clogging. For instance, open surfaces, feed holes,hoses, piping, and/or the like may accumulate unwanted carbon-basedparticulate matter as a by-product of synthetic procedures performed tocreate carbon-based particle 100A. A central issue observed in amicrowave reactor may include this tendency to experience clogging inand/or along orifices, the reason being related to walls and othersurfaces exposed to in-flowing gaseous carbon-containing species havingcarbon solubility as well. Therefore, is it possible to unwantedly growon the walls of a reaction chamber and/or on the exit tube. Over time,those growths will extend out and ultimately impinge flow and can shutdown chemical reactions occurring within the reactor and/or reactionchamber. Such a phenomena may be akin to tube, such as an exhaust, wallbuild-up of burnt oil in a high-performance or racing internalcombustion engine, where, instead of burning, such as combusting,fossil-fuel based gasoline, methane is used to result in the unwanteddeposit of carbon on reaction chamber wells since metal inside thereaction chamber itself has a carbon solubility level.

Although methane is primarily used to create carbon-based particle 100A,any carbon-containing and/or hydrocarbon gas, like C₂ or acetylene orany one or more of: C₂H₂, CH₄, butane, natural gas, biogas, such as thatderived from decomposition of biological matter, will likewise functionto provide a carbon-containing source.

The described uncontrolled and unwanted carbon growth within exposedsurfaces of a microwave reactor may be compared to that occurring withinan internal combustion engine exhaust manifold, as opposed to thecylinder bore, of the engine, especially where the plume of plasma, suchas hot and excited gas about to enter into the plasma phase, is at theonset of the manifold, and burnt gas and carbon-based fragments aretraveling down and plugging-up flow through the manifold, cross-pipes,and catalytic converter, and exit-pipes. Process conditions maytherefore be proactively tuned to adjust and therefore accommodate forpotential carbon-build-up in the microwave reactor, which relies on thepresence of a plasma for hydrocarbon gas cracking. To maintain thisplasma, a certain set of conditions must be maintained, otherwiseback-pressure accumulation can destroy the plasma prior to its creationand subsequent ignition, etc.

Thermal Reactor

In the alternative or addition to synthesis of carbon-based particle100A in a microwave reactor, structured carbons can be created bythermally cracking hydrocarbons by heat application in a reactor, suchas a thermal reactor. Example configurations may include exposure ofincoming carbon-based gaseous species, such as any one or more of theaforementioned hydrocarbons, to a heating element, similar to a wire ina lightbulb.

The heating element heats up the inside of a reaction chamber whereincoming carbon-containing gas is ionized. The carbon-containing gas isnot burnt, due to the absence of sufficient oxygen to sustaincombustion, but is rather ionized from contact with incoming thermalradiation, such as in the form of heat, to cause nucleation ofconstituent members of carbon-based particle 100A, and ultimatelysynthesize, via nucleation, carbon-based particle 100A, and/orcarbon-based particles similar to it, in its entirety. In thermalreactors, at least some of the observed nucleation of carbon-basedparticles can occur on walls or on the heating element itself.Nevertheless, particles can still nucleate which are small enough to becracked by the speed of flowing gas, where such particles are capturedto assist in the creation of carbon-based particle 100A.

Cracked carbons can be used to create a multi-shell fullerene carbonnano-onion (CNO), and/or other fullerenes, and smaller fractions ofcarbons with fullerene internal crystallography. In comparing synthesisof carbon-based particle 100A via microwave and thermal reactors, thefollowing distinctions have been observed:

-   -   microwave reactors can provide tuning capabilities suitable to        provide a broader range of allotropes of carbon; whereas,    -   thermal reactors tend to allow for the fine-tuning of process        parameters, such as heat flow, temperature, and/or the like, to        achieve the needs of specific end-use application targets of        carbon-based particle 100A.

For instance, thermal reactors are currently being used to build Li Selectrochemical cell electrodes, such as anodes and cathodes. Typicaltreatment process temperatures range in the thousands of Kelvin, toproduce the carbon-based particle 100A and/or carbon-based aggregatesassociated therewith, when compressed, have an electrical conductivitygreater than 500 S/m, or greater than 5,000 S/m, or from 500 S/m to20,000 S/m. Optimal performance has been observed at between 2,000-4,000K.

Carbon-Based Particle—Physical Properties & Implementation in Li Ion andLi S Batteries

Any of the carbon-based structures shown in FIG. 1A-1F may beincorporated into a secondary battery electrode, such as that of alithium (Li) ion battery, as substantially set forth by Lanning, et al.,“Lithium Ion Battery and Battery Materials”, U.S. Pat. Pub. No.2019/0173125, published on Jun. 6, 2019, incorporated by referenceherein in its entirety. Disclosed implementations typically relate to Liincorporation or infusion within the anode, although carbon-basedsystems can be revised for compatibility and integration with thecathode, especially in Li S systems where microconfinement of S isdesirable to mitigated unwanted polysulfide (PS) shuttle and cellself-discharge.

Particulate carbon contained in and/or otherwise associated withcarbon-based particle 100A may be implemented in a Li ion battery anodeor cathode as a structural and/or electrically conductive material andbe characterized by hierarchical porous network 100E with a widedistribution of pore sizes, also referred to as a multi-modal pore sizedistribution. For example, particulate carbon can contain multi-modaldistribution of pores in addition or in the alternative to thecontiguous microstructures 107E, as shown in FIG. 1E, that at least inpart further define open porous scaffold 102A with one or more thediffusion pathways 109E. Such pores may have sizes from 0.1 nm to 10 nm,from 10 nm to 100 nm, from 100 nm to 1 micron, and/or larger than 1micron. Pore structures can contain pores with a multi-modaldistribution of sizes, including smaller pores, with sizes from 1 nm to4 nm, and larger pores, with sizes from 30 to 50 nm. Such a multi-modaldistribution of pore sizes in carbon-based particle 100A can bebeneficial in Li S battery system configurations, where S-containingcathodes in Li S batteries can be confined in the pores 105E having thedimension 103E of approximately less than 1.5 nm or in the range 1 to 4nm in size. Control of saturation and crystallinity of S and/or ofgenerated S compounds in a carbon-based cathode including the contiguousmicrostructures 107E in larger pores or pathways ranging from 30 to 50nm in size, or pores greater than twice the size of solvated lithiumions (such as lithium, Li, ions 108E), can enable and/or facilitaterapid diffusion, or, mass transfer, of solvated Li ions in the cathode.

As introduced earlier, the lithium-sulfur battery, abbreviated as a Li—Sbattery, is a type of rechargeable battery, notable for its highspecific energy. A Li—S battery, can include sulfur (S) infiltrated orinfused for confinement within the pores 105E and along exposed surfacesof the contiguous microstructures 107E of mesoporous particle 100D.Accordingly, S can infiltrate the open porous scaffold 102A, whenincorporated into a cathode of a Li S battery, to deposit on internalsurfaces of the carbon-based particle 100A, 100D and/or within thecontiguous microstructures 107E, as shown in FIG. 1E and by schematic100F shown in FIG. 1F, which shows intermediate steps associated withthe reduction of sulfur to the sulfide ion (S²⁻). Carbon-BasedParticle—Formed to Address Polysulfide (PS)-Related Challenges

Seeking to address at least some of the challenges associated with suchpolysulfide (PS) systems, carbon-based particle 100A and cathodic activematerial form a meta-particle framework, where cathodic electroactivematerials, such as elemental sulfur that may form PS compounds 100F asshown in FIG. 1F, are arranged within carbon pores/channels, such aswithin any one or more of the contiguous microstructures 107E, as shownin FIG. 1E, including pores 104E, 105E, and/or pathways 106E and/or thediffusion pathways 109E. S can be, for example, substantiallyincorporated within the contiguous microstructures 107E at a loadinglevel that represents 35-100% of the total weight/volume of activematerial in carbon-based particle 100A and/or 100E overall.

This type of organized particle framework can provide a low resistanceelectrical contact between the insulating cathodic electroactivematerials, such as elemental S, and the current collector whileproviding relatively high exposed surface area structures that arebeneficial to overall specific capacity and that may assist Li ionmicro-confinement as enhanced by the formation of Li S compoundstemporarily retained in the contiguous microstructures 107E, such as inthe pores 105E, to in turn control and direct migration of Li ions asmay be related to electric current conduction in a battery electrodeand/or system. Implementations of carbon-based particle 100A can alsobenefit cathode, as well as anode, stability by trapping at least someportion of any created polysulfides by using tailored structures, suchas that shown by the contiguous microstructures 107E, to activelyprevent them from unwantedly migrating through electrolyte to the anoderesulting in unwanted parasitic chemical reactions associated withbattery self-discharge.

Migration of Polysulfides (PS) Furing Li S Battery System Usage

As introduced earlier, with reference to PS shuttle mechanisms observedin Li S battery electrodes and/or systems, PS dissolve very well inelectrolytes. This causes another Li—S cell characteristic, the shuttlemechanism. The PS S_(n2)—that form and dissolve at the cathode, diffuseto the Li anode and are reduced to Li₂S₂ and Li₂S. The PS species S_(n)²⁻ that form at the cathode during discharging dissolve in theelectrolyte there. A concentration gradient versus the anode develops,which causes the PS to diffuse toward the anode. Step by step, the PSare distributed in the electrolyte. Subsequent high-order PS speciesreact with these compounds and form low-order polysulfides S_((n-x)).This means that the desired chemical reaction of sulfur at the cathodepartly also takes place at the anode in an uncontrolled fashion, whereboth chemical and electrochemical reactions are conceivable, whichnegatively influences overall cell characteristics.

If low-order PS species form near the anode, they diffuse to thecathode. When the cell is discharged, these diffused species are furtherreduced to Li₂S₂ or Li₂S. As a result, the cathode reaction partly takesplace at the anode during the discharging process or, rather, the cellself-discharges. Both are undesirable effects decreasing specificcapacity. In contrast, the diffusion to the cathode during the chargingprocess is followed by a re-oxidation of the PS species from low orderto high order. These PS then diffuse to the anode again. This cycle isgenerally known as the shuttle mechanism, which can be very pronounced,it is possible that a cell can accept an unlimited charge to bechemically short-circuited. In general, the shuttle mechanism causes aparasitic sulfur active matter loss. This is due to the uncontrolledseparation of Li₂S₂ and Li₂S outside of the cathode area and iteventually causes a considerable decrease in cell cycling capability andservice life. Further aging mechanisms can be an inhomogeneousseparation of Li₂S₂ and Li₂S on the cathode or a mechanical cathodestructure breakup due to volume changes during cell reaction.

Pores of Carbon-Based Particle Confine Sulfur and Prevent PS Shuttle tothe Anode

To address the phenomenon of PS shuttling, any one or more of thecontiguous microstructures 107E of carbon-based particle 100A in acathode can provide a region formed with an appropriate dimension, suchas the pores 105E having the dimension 103E of less than 1.5 nm, todrive the creation of lower order polysulfides, such as S and Li₂S, andtherefore prevent the formation of the higher order solublepolysulfides, Li_(x)S_(y) with y greater than 3, that facilitate Lishuttle, such as loss to the anode. As described herein, the structureof the particulate carbon and the cathode mixture of materials can betuned during particulate carbon formation within a microwave plasma orthermal reactor. In addition, cathodic electroactive materials, such aselemental sulfur, solubility and crystallinity in relation to Li phaseformation, can be confined/trapped within the micro- and/or meso-porousframework of the contiguous microstructures 107E of carbon-basedparticle 100A.

A multi-modal distribution of pore sizes can be indicative of structureswith high surface areas and a large quantity of small pores that areefficiently connected to the substrate and/or current collector viamaterial in the structure with larger feature sizes to provide moreconductive pathways through the structure. Some non-limiting examples ofsuch structures are fractal structures, dendritic structures, branchingstructures, and aggregate structures with different sized interconnectedchannels composed of pores and/or particles that are roughly cylindricaland/or spherical.

Example particulate carbon materials used in the Li ion or Li Sbatteries described herein are described in U.S. Pat. No. 9,997,334,entitled “Seedless Particles with Carbon Allotropes,” which is assignedto the same assignee as the present application, and is incorporatedherein by reference. The particulate carbon materials can containgraphene-based carbon materials that include a plurality of carbonaggregates, each carbon aggregate having a plurality of carbonnanoparticles, each carbon nanoparticle including graphene, optionallyincluding multi-walled spherical fullerenes, and optionally with no seedparticles such as with no nucleation particle. In some cases, theparticulate carbon materials are also produced without using a catalyst.The graphene in the graphene-based carbon material has up to 15 layers.A ratio of carbon to other elements, except hydrogen, in the carbonaggregates is greater than 99%. A median size of the carbon aggregatesis from 1 micron to 50 microns, or from 0.1 microns to 50 microns. Asurface area of the carbon aggregates is at least 10 m²/g, or is atleast 50 m²/g, or is from 10 m²/g to 300 m²/g or is from 50 m²/g to 300m²/g, when measured using a Brunauer-Emmett-Teller (BET) method withnitrogen as the adsorbate. The carbon aggregates, when compressed, havean electrical conductivity greater than 500 S/m, or greater than 5,000S/m, or from 500 S/m to 20,000 S/m.

Distinctions Between the Carbon-Based Particles and ConventionalTechnology

Conventional composite-type Li-ion or Li S battery electrodes may befabricated from a slurry cast mixture of active materials, includingconductive additives such as fine carbon black and graphite for usage ina battery cathode at a specific aspect ratio, and polymer-based bindersthat are optimized to create a unique self-assembled morphology definedby an interconnected percolated conductive network. While, inconventional preparations or applications, additives and binders can beoptimized to improve electrical conductivity there-through by, forexample, offering lower interfacial impedance and thereforecorrespondingly yield improvements in power performance and delivery,they represent a parasitic mass that also necessarily reduces specific,also referred to as gravimetric, energy and density, an unwanted endresult for current demanding high-performance battery applications.

To minimize losses due to parasite mass, such as that caused byincreased active and/or inactive ratio, and concurrently enable fasteraccess of electrolyte to the complete surface of an electrode, thediffusion pathways 109E may be re-oriented to effectively shorten Li iondiffusion path lengths for charge transfer. The hierarchical pores 101Aand/or the open porous scaffold 102A may be created from reduced-sizecarbon particles and/or active materials down to nanometer scales. Theexternal specific surface area (SSA), defined as the total surface areaof a material per unit of mass, with units of m²/kg or m²/g, or solid orbulk volume (units of m²/m³ or m⁻¹) is a physical value of any one ormore of the presently disclosed carbon particles that can be used todetermine the type and properties of a material. For instance, the SSAof a sphere increases with decreasing diameter. However, as the particlesize is decreased down into the nanometer size range there areassociated attractive van der Waal forces that can impede dispersion,facilitate agglomeration, and thereby increase cell impedance and reducepower performance.

Another approach to shortening ion diffusional pathways, referring tothe diffusion pathways 109E shown in FIG. 1E, is to uniquely engineerthe internal porosity of the constitutive carbon-based particles, suchas those created by the agglomerations 101B to create the contiguousmicrostructures 107E. A surface curvature can be referred to as a poreif its cavity is deeper than it is wide. As a result, this definitionnecessarily excludes many nanostructured carbon materials where just theexternal surface area is modified, or in close packed particles wherevoids, such as intra-particular spaces or regions, are created betweenadjacent particles, as in the case of a conventional slurry castelectrode.

With respect to the engineering, referring to the synthesis, creation,formation, and/or growth of carbon-based particle 100A either in-flightin a microwave-based reactor or via layer-by-layer deposition in athermal reactor as substantially described earlier, reactor processparameters may be adjusted to tune the size, geometry, and distributionof hierarchical pores 101A and/or the contiguous microstructures 107Ewithin carbon-based particle 100A. Hierarchical pores 101A and/or thecontiguous microstructures 107E within carbon-based particle 100A may betailored to achieve performance figures particularly well-suited forimplementation in high-performance fast-current delivery devices, suchas supercapacitors.

As generally described earlier, a supercapacitor (SC), also called anultracapacitor, is a high-capacity capacitor with a capacitance valuemuch higher than other capacitors, but with lower voltage limits, thatbridges the gap between electrolytic capacitors and rechargeablebatteries. It typically stores 10 to 100 times more energy per unitvolume or mass than electrolytic capacitors, can accept and delivercharge much, much faster than batteries, and tolerates many more chargeand discharge cycles than rechargeable batteries.

In many of the available off-the-shelf commercial carbons used in earlysupercapacitor development efforts, there were worm-like narrow poreswhich became a bottleneck or liability when operating at high currentdensities and fast charge- and discharge rates, as electrons mayencounter difficulty in flow through, in or around such structures orpathways. Even though pore dimensions were fairly uniform but stilladjustable to accommodate a wide range of length scales, real-lifeachievable performance was still self-limited, as based on thestructural challenges inherent to the worm-like narrow pores.

Compared to conventional porous materials with uniform pore dimensionsthat are tuned to a wide range of length scales, the presently disclosed3D hierarchical porous materials, such as that shown by hierarchicalpores 101A and/or the contiguous microstructures 107E withincarbon-based particle 100A, may be synthesized to have well-defined poredimensions, such as the contiguous microstructures 107E including pores104E, 105E, and/or pathways 106E and/or the diffusion pathways 109E andtopologies to overcome the shortcomings of conventional mono-sizedporous carbon particles by creating multi-modal pores and/or channelshaving the following dimensions and/or widths:

-   -   meso (2 nm<d_(pore)<50 nm) pores;    -   macro (d_(pore)>50 nm) pores 201A to minimize diffusive        resistance to mass transport; and,    -   micro (d_(pore)<2 nm) pores 202 to increase surface area for        active site dispersion and/or ion storage, capacitance relating        to density and number of ions that can be stored within a given        pore size, such as that shown by the pore 105E having the        dimension 103E in FIG. 1E.

Although no simple linear correlation has been experimentallyestablished between surface area and capacitance, the carbon-basedparticle 100A provides optimal micropore size distributions and/orconfigurations that are different for each intended end-use applicationand corresponding voltage window. To optimize capacitance performance,the carbon-based particle 100A may be synthesized with very narrow poresize distributions (PSD); and, as desired or required voltages areincreased, larger pores are preferred. Regardless, currentstate-of-the-art supercapacitors have provided a pathway to engineeringthe presently disclosed 3D hierarchical structured materials forparticular end-use applications.

In supercapacitors, capacitance and power performance is primarilygoverned by, for example:

-   -   surface area of the pore wall;    -   size of pore; and    -   interconnectivity of the pore channels, which affects electric        double layer performance.

In contrast, Li ion and/or Li—S storage batteries undergo faradaicreduction/oxidation reactions within the active material and thereby mayneed many of the Li ion transport features of a supercapacitor, such asefficiently oriented and/or shortened Li ionic diffusion pathways.Regardless, in any application, including a supercapacitor as well as atraditional Li ion or Li S secondary battery, a 3D nanocarbon-basedframework/architecture, such as that defined open porous scaffold 102A,can provide continuous electrical conducting pathways, such as acrossand along electrically conductive interconnected agglomerations ofgraphene sheets 101B, alongside, for example, highly-loaded activematerial having high areal and volumetric specific capacity.

Carbon-Based Particle Used as a Formative Material for a Cathode

To address prevailing issues with relatively low electrical and ionicconductivities, volume expansion and polysulfide (PS) dissolution incurrent Li S cathode electrode designs, the carbon-based particle 100Ahas the hierarchical pores 101A and/or the contiguous microstructures107E formed therein to define the open porous scaffold 102A, whichincludes the pores 105E with microporous textures having the dimension103E, such as approximately less than 1.5 nm or 1-4 nm cavities suitableto confine elemental sulfur and/or Li S related compounds. The openporous scaffold 102A, while confining sulfur, also provides a hostscaffold-type structure to manage S expansion to ensure electronconduction across the sulfur-carbon (S—C) interface, such as at contactand/or interfacial regions of S and C within the pores 105E by, forexample, tailored in-situ nitrogen (N) doping of the carbon (C) withinthe reactor. Confining S within a nanometer (nm) scale cavity, such aspores 105E with microporous textures 103E, favorably alters both:

-   -   the equilibrium saturation, such as the solubility product; and,    -   crystalline behavior of S, such that S remains confined as may        be necessary for desirable electrical conduction upon        dissociation of Li S compounds, etc. within microporous textures        or the pores 105E having the dimension 103E, with no external        driving force required to control unwanted PS migration to the        anode electrode.

-   As a result, the dimension 103E of the pores 105E results in no need    for separators that attempt to impede polysulfide (PS) diffusion    while, at the same time, negatively impacting cell impedance, such    as the effective resistance of an electric circuit or component to    alternating current, arising from the combined effects of ohmic    resistance and reactance, and polarization. By using carbon with    optimum, relative to elemental S, Li and/or Li S micro-confinement,    and non-optimum multi-modal, referring to the contiguous    microstructures 107E including pores 104E, 102E, and/or 103E, or    (alternatively) bi-modal pore distributions, the carbon-based    particle 100A demonstrates operation of the principle of    micro-confinement in properly optimized structures.

Such optimized structures include incorporation with the agglomerations101B, which can themselves be prepared to include parallel stackedgraphene layers, such as that produced from graphite having strong (002)dimensionality to random few-layer (FL) graphene with nanoscopic poreshaving low (002) dimensionality. FIGS. 1G and 1H show systematicintercalation of Li ions in carbon lattices and structures, beingpositioned within individual graphene layer cells in FIG. 1G, andin-between adjacent and parallel graphene layers in FIG. 1H. Theconfigurations shown in FIG. 1H can include multiple stages, includingStages 1 through 3, each state representing various dimensions andspacing levels of graphite layer planes to yield a theoretic specificcapacity of approximately 372 mAh/g at the cathode, or more.

FIG. 2 shows an evolution beyond conventional adjacent stacked FLgraphene layers shown in Stages 1 to 3 in FIG. 1H, where cavities areformed extending depth-wise into several of the adjacent stacked FLgraphene layers, each layer having tunable D-spacing ranging fromapproximately 3.34 Å to 4.0 Å, or 3 Å to 20 Å. Accordingly, Li ions canbe intercalated between adjacent graphene layers as well as forming alayer on exposed surfaces of the cavity, also referred to as ananoscopic pore, to yield a specific capacity range in excess of 750mAh/g. When viewed collectively, an example enlarged section of the 3Dself-assembled binder-less carbon-based particle can coalesce to form acarbon-based network, lattice, scaffold, or particle, which may includeany one or more of the presently-disclosed carbon-based structures shownin FIG. 1A through FIG. 1E, according to some implementations. Thecarbon-based network can include any one or more of a plurality ofmacropores or micropores 202.

The carbon-based particle 100A also provides the ability to effectivelyload or infuse carbon scaffold 300 shown in FIG. 3 with elemental Li,such as that provided from molten Li metal or a vapor derivativethereof. The carbon scaffold 300 can be created in-reactor by either:

-   -   layer-by-layer deposition of multiple carbon-based particles        100A by a slurry-case method; or,    -   by a continuous sequence of a group of plasma spray-torches, as        shown by plasma spray-torch system 400B in FIG. 4B, with sulfur,        such as elemental sulfur.

For Li S battery performance to reliably exceed conventional Li ionbatteries, industry-scalable techniques must achieve high S loading,such as >70% sulfur per unit volume, relative to all additives andcomponents of a given cathode template, while maintaining the nativespecific capacity of the S active material. Attempts to incorporate Sinto a cathode host, such as by any one or more of, performedindependently or in any combination: electrolysis, wet chemical, simplemixing, ball milling, spray coating, and catholytes, have either notfully incorporated the S as desirable, or are otherwise not economicallyscalable or manufacturable.

Unlike melt infiltration where small pores are thermodynamicallyinaccessible, presently disclosed synthetic approaches can use anisothermal vapor technique, introduced and reacted at substantiallyatmospheric pressure, where the high surface free energy of nanoscalepores or surfaces drives the spontaneous nucleation of sulfur containingliquids until a conformal coating of sulfur and/or lithium-containingcondensate is reached on inner-facing surfaces of hierarchical pores101A and/or the contiguous microstructures 107E. In essence, uniquevapor infusion process infuses sulfur into fine pores, such as any oneor more of hierarchical pores 101A and/or the contiguous microstructures107E and/or pores 104E, 105E and/or pathways 106E and/or the diffusionpathways 109E at the core of carbon-based particle 100A, and thereforenot just at its surface.

Carbon-Based Particles Used to Create an Electrically ConductiveScaffold

Carbon-based particle 100A, may be fabricated any number of ways usingboth known and novel techniques disclosed herein, including:

-   -   slurry-casting, referring to conventional metalworking,        manufacturing and/or fabrication techniques in which a liquid        material is usually poured into a mold, which contains a hollow        cavity of the desired shape, and then allowed to solidify; or    -   a plasma spray-torch system 400B, such as that shown in FIG. 4B,        which may be used to perform layer-by-layer deposition to grow        carbon-based particle 100A incrementally.

Either technique as described above, or any other known or novelfabrication techniques, may be used to produce carbon scaffold 300,shown in FIG. 3, in a graded manner. Control over the electricalgradients can result in the carbon scaffold 300 having varying degreesof electrical conductivity as dictated at least in part by any one ormore of electrical gradients and ionic conductive gradients, describedas follows:

-   -   electrical gradients can be defined by the graphene sheets 101B        substantially orthogonally fused together form the open porous        scaffold 102A, where electrical conduction occurs along and        across contact points of graphene sheets 101B; and,    -   ionic conductive gradients, such as Li ion transport, movement,        or migration through the hierarchical pores 101A and the        contiguous microstructures 107E, can be benefited, in certain        configurations of the carbon-based particle 100 by the effective        shortening of the diffusion pathways 109E throughout thickness        of the carbon scaffold 300B in the vertical height direction A        as shown in FIG. 3B to, for example, permit Li ions intercalated        between adjacent few-layer graphene sheets, such as the graphene        sheets 101B, to escape and migrate toward a liquid electrolyte        surrounding the carbon scaffold 300B on route to the cathode        curing electrochemical cell discharge-charge cycling.

Reference has been made throughout the presently disclosedimplementations to various forms of carbon synthesized in-flight withina reactor to create the graphene sheets 101B, which are interconnectedand conduct electricity along contact points and may vary in shape,size, position, orientation, and/or structure. Such variances can beinfluenced in differences in crystallinity and the particular type ofcarbon allotrope(s) used for creation of electrically conductiveinterconnected agglomerations of graphene sheets 101B. Crystallinityimplies the degree of structural order in a solid. In a crystal, atomsor molecules are arranged in a regular, periodic manner. The degree ofcrystallinity therefore has a significant influence on hardness,density, transparency, and diffusion.

Accordingly, the carbon-based particle 100 can be produced in the formof an organized scaffold, such as a carbon-based scaffold, out of areactor or be created during post-processing activities taking placeoutside of primary synthesis within a reactor.

Plasma processing and/or plasma-based processing, may be conductedwithin a reactor as disclosed by Stowell, et al., “Microwave ChemicalProcessing Reactor”, U.S. Pat. No. 9,767,992, issued on Sep. 19, 2017,where supply gas is used to generate a plasma in the plasma zone toconvert a process input material, such as methane and/or other suitablehydrocarbons in a gaseous phase, into separated components in a reactionzone to facilitate in-flight synthesis of carbon-based materials.

Alternative to synthesis by or within a microwave reactor as describedabove, thermal energy may be directed toward or near carbon-containingfeedstock materials supplied in a gaseous phase onto a sacrificialsubstrate 306 of the carbon scaffold 300 shown in FIG. 3 to sequentiallydeposit multiple layers of carbon-based particles 100A by, for example,plasma spray-torch system 400B shown in FIG. 4B. Such particles may beeither fused together in-flight, in a microwave reactor, or deposited,in a thermal reactor, in a controlled manner to achieve varyingconcentration levels of carbon-based particles 100A to therefore, inturn, achieve graded electrical conductivity proportionate toconcentration levels of carbon-based particles 100A in the carbonscaffold 300. Such procedures may be used to formulate porouscarbon-based electrode structure, such as carbon scaffold 300, that hasa high degree of tunability, such as in electrical conductivity andionic transport, while also eliminating many production steps andotherwise retaining a conventional outward appearance.

The open porous scaffold 102A can be produced with an open cellularstructure such that a liquid-phase electrolyte can easily infiltrateinto various pores, such as any one or more of the pathways, voids, andthe like of the contiguous microstructures 107E, therein. Skeletalportions of open porous scaffold 102A may be referred to as a matrix ora frame, and pores, such as hierarchical pores 101A and/or thecontiguous microstructures 107E, can be infiltrated with a fluid, liquidor gas, whereas, skeletal material is usually formed as a solidmaterial.

Porosity of the Carbon-Based Particle

A porous medium, such as carbon-based particle 100A, can becharacterized by its porosity. Other properties of the medium, such aspermeability, tensile strength, electrical conductivity, and tortuosity,may be derived from the respective properties of its constituents, ofsolid matrix and fluid interspersed therein, as well as media porosityand pore structure. Carbon-based particle 100A having the contiguousmicrostructures 107E interspersed throughout therein can be created outof a reactor to achieve desirable porosity levels that are conducive forLi ion diffusion. Related to such Li ion diffusion, the graphene sheets101B facilitate electron conduction along contact points thereof whilealso allowing for electrons to reunite with positive Li ions at reactionsites.

Regarding, porosity and tortuosity of open porous scaffold 102A ofcarbon-based particle 100A, an analogy may be made to marbles in a glassjar. Porosity, in this example, refers to spacing between the marblesthat allows liquid-phase electrolyte to penetrate into void spacesbetween the marbles, similar to the contiguous microstructures 107E thatdefine the diffusion pathways 109E within the carbon-based particle100A. The marbles themselves may be like swiss cheese, by allowingelectrolyte not only to penetrate in cracks between the graphene sheets101B, but also into each graphene sheet themselves, an individualgraphene sheet is shown in FIG. 1C. In this example as well as others,the relative shortening of the diffusion pathways 109E refers to howlong it takes Li ions infiltrated therein by, for example, capillaryaction to contact active material, such as S confined within pores 105E.The diffusion pathways 109E accommodate convenient and rapidinfiltration and diffusion of electrolyte, which may contain Li ions,into carbon-based particle 100A, which can then be grown or otherwisesynthesized further to create carbon scaffold 300 with graded electricconductivity.

The shortening of the diffusion pathways 109E refers toward theshortening of diffusion lengths through which Li ions move within openporous scaffold 102A in carbon scaffold 300 and not of the activematerial, such as S, itself confined within the pores 105E of thecontiguous microstructures 107E. This is on contrast to conventionaltechniques that require the diffusion length of the active material tobe shortened only by making the thickness of the active material lesseror smaller. The diffusion pathways 109E within the contiguousmicrostructures 107E can act as Li ion buffer reservoirs by controllingflow and/or transport of Li ions therein to provide a freer flowingstructure for Li ion transport therein, as may be beneficial for Li ionconfinement, as reacted with S coated on exposed carbon surfaces of thepores 105, and later Li ion transport during electrochemical cellcharge-discharge cycles. Transport of Li ions throughout the diffusionpathways 109E in the general directions shown in FIG. 1F can take placein a liquid electrolyte initially infused and captured within openporous scaffold 102A, where such infusion of electrolyte occurs prior tocyclic carbon scaffold 300 usage in discharge-charge cycles.

Examples exist permitting for the initial diffusion and distribution ofliquid-phase electrolyte in open porous scaffold 102A of carbon-basedparticle 100A to fill up and occupy hierarchical pores 101A and/or thecontiguous microstructures 107E prior to usage of carbon scaffold 300,synthesized or otherwise created by layer-on-layer deposition ofcarbon-based particles 100A. Vacuum or air may also be used to fillhierarchical pores 101A and/or the contiguous microstructures 107E,which may allow or assist with wetting of electrolyte withcarbon-containing exposed surfaces within open porous scaffold 102A.

Li ions bounce from one location to another by a chain reaction, similarto the striking of newton balls, where one hits to result in forcetransference resulting in the movement of other balls. Similarly, eachLi ion moves a relatively short distance, yet remains able to move greatnumbers of Li ions in the collective through this type of chain reactionas described. The extent of individual Li ion movement may be influencedby the quantity of Li ions supplied altogether to carbon scaffold 300Bvia capillary infusion into open porous scaffold 102A, as may be thecrystallographic arrangement of Li ions and/or particles in, around, orwithin agglomerations of graphene sheets 101B.

Electrochemical Cell Anode or Cathode Created from Carbon Scaffold

The carbon scaffold 300, shown in FIG. 3, can be integrated in batteryor supercapacitor applications, battery types including Li ion batteriesand Li S batteries. The carbon scaffold 300 can be incorporated intoeither the anode or the cathode for Li ion and Li S battery systems,although the contiguous microstructures 107E will need to be prepared toconfine S in the pores 105E or elsewhere to accommodate the creation andconfinement of polysulfides (PS) as well as the control of PS migration.An example battery system may include an electrochemical cell configuredto supply electric power to a system. The electrochemical cell may havean anode containing an anode active material, a cathode containing acathode active material, a porous separator disposed between the anodeand the cathode, and an electrolyte in ionic contact with the anodeactive material and the cathode active material.

The anode and cathode may include sacrificial substrate 306, that iselectrically conductive, with a first layer deposited there-upon as afirst contiguous film having a first concentration of carbon-basedparticles 100A shown as carbon-based particles 302 in FIG. 3, such thata redundant description of the same is omitted.

A porous arrangement formed in the carbon scaffold 300 as defined by thecarbon-based particles 302, which are synonymous with and usedinterchangeably with multiple carbon-based particle 100A adjoinedtogether, and smaller carbon particles 304 interspersed throughout thecarbon scaffold 300. The porous arrangement of the carbon scaffold 300receives electrolyte dispersed therein for Li ion transport throughinterconnected hierarchical pores 101A and/or the contiguousmicrostructures 107E that, similar to individual carbon-based particles100A and/or 302, define one or more channels including:

-   -   microporous frameworks defined by a dimension 101E of >50 nm        that provide tunable Li ion conduits;    -   mesoporous channels defined by a dimension 102E of about 20 nm        to about 50 nm, generally defined under IUPAC nomenclature and        referred to as mesopores or mesoporous, that act as Li        ion-highways for rapid Li ion transport therein; and    -   microporous textures defined by a dimension 103E of <4 nm for        charge accommodation and/or active material confinement.

The first layer including a first concentration of carbon-basedparticles 100A and/or 302 can be configured to demonstrate an electricalconductivity ranging from 500 S/m to 20,000 S/m. A second, or anysubsequent, layer can be deposited on the first, or any preceding,layer. The second layer can include a second contiguous film formed by asecond concentration of carbon-based particles 100A and/or 302 incontact with each other to yield a second electrical conductivityranging from 0 S/m to 500 S/m, or otherwise lower than the firstelectrical conductivity.

Carbon scaffold 300 may be prepared for subsequent Li infiltration,referred to herein as being pre-lithiated, and later infused with Li ionliquid solution via capillary action to create lithiated carbon scaffold400A as shown in FIG. 4A. Film layers 406A, 408A, 410A, and 412A, eachhaving defined thicknesses in the vertical direction extending from thecurrent collector, may be synthesized in-flight in a microwave reactor,or deposited layer-by-layer in or out of a thermal reactor. Film layers406A, 408A, 410A, and 412A have varying electrical conductivity rangingfrom high, such as at film layer 406A, to low, such as at film layer412A, in a direction orthogonal and away from the current collector,which may also be a sacrificial and/or electrically conductivesubstrate. In an example configuration, each layer of the film layers406A, 408A, 410A, and 412A can be produced with a defined, and aprogressively declining, concentration of carbon-based particles 302 toachieve particular electrical resistance values, such as where:

-   -   The film layer 406A is produced with a relatively high defined        concentration of carbon-based particles 302 conducive for low Li        ion transport and low electrical resistance, at <1,000Ω,        suitable for high electrical conductivity;    -   the film layers 408A and 410A are produced with systematically        decreasing electrical conductivity by engineering the        carbon-based particles 302 to demonstrate desirable interfacial        surface tension to promote wetting of exposed carbon surfaces        with molten Li metal; and    -   the film layer 412A is produced with a relatively low defined        concentration of carbon-based particles 302 conducive for high        Li ion transport and high electrical resistance,        at >1,000-10,000Ω, suitable for high electrical resistance.

Varying electrical conductivity may be at least partially proportionateto interfacial surface tension of a Li ion solution infiltrated into theporous arrangement of the open porous scaffold. Infiltration of the Liion solution (such as including the Li ions 108E) can be performed viacapillary infusion engineered to promote wetting of surfaces of openporous scaffold 102A exposed to Li ion solution. The diffusion pathways109E, as shown in FIG. 1E, ensure that deposition and strippingoperations associated with one or more oxidation-reduction, alsoreferred to as redox, reactions occurring within carbon-based particles100A and/or 302B are uniform. Electroactive material can reside in thepores 105E of the contiguous microstructures 107E when they are used toform the open porous scaffold 102A, which itself may be incorporatedwithin any one or more of the anode and the cathode. In someimplementations, the contiguous microstructures 107E may be formed fromor otherwise contain single-layer graphene (SLG), as shown in FIG. 1C,and/or few-layer graphene (FLG) including from 1 to 10 graphene planes,shown as the agglomerations 101B of multiple layers of the graphenesheets 101C in FIG. 1B. Groupings of the graphene sheets 101C can bepositioned in a substantially aligned orientation along a vertical axisand fused together at substantially orthogonal angles. Anode activematerial or cathode active material may have a specific surface areafrom approximately 500 m²/g to 2,675 m²/g when measured in a driedstate, and may contain a graphene material suitable for lithiation, thegraphene material comprising any one or more of pre-lithiated graphenesheets, pristine graphene, graphene oxide, reduced graphene oxide,graphene fluoride, graphene chloride, graphene bromide, graphene iodide,hydrogenated graphene, nitrogenated graphene, boron-doped graphene,nitrogen doped graphene, chemically functionalized graphene, physicallyor chemically activated or etched versions thereof, conductive polymercoated or grafted versions thereof, and/or combinations thereof.

In any one or more of the discussed examples in relation to lithiatedcarbon scaffold 400A, electrically conductive interconnectedagglomerations of graphene sheets 101B are sintered together to formopen porous scaffold independent of a binder, however alternativeexamples do exist where a binder is used. Configurations with or withouta binder may each involve open porous scaffold 102A acting or serving asan active lithium intercalating structure with a specific capacity ofapproximately 744-1,116 mAh/g, or more. Also, examples include thepreparation of graphene sheets 101B using chemically functionalizedgraphene, involving the surface functionalization thereof, comprisingimparting to open porous scaffold 102A a functional group selected fromquinone, hydroquinone, quaternized aromatic amines, mercaptan,disulfide, sulfonate (—SO₃), transition metal oxide, transition metalsulfide, other like compounds or a combination thereof.

The current collector shown in FIG. 4A, is, for example, at leastpartially foam-based or foam-derived and is can be selected from any oneor more of metal foam, metal web, metal screen, perforated metal,sheet-based 3D structure, metal fiber mat, metal nanowire mat,conductive polymer nanofiber mat, conductive polymer foam, conductivepolymer-coated fiber foam, carbon foam, graphite foam, carbon aerogel,carbon xerogel, graphene foam, graphene oxide foam, reduced grapheneoxide foam, carbon fiber foam, graphite fiber foam, exfoliated graphitefoam, and combinations thereof.

Anode or cathode electrically conductive or insulative material,referred to herein as active material can include any one or more ofnanodiscs, nanoplatelets, nano-fullerenes, carbon nano-onions (CNOs),nano-coating, or nanosheets of an inorganic material selected from:

-   -   bismuth selenide or bismuth telluride,    -   transition metal dichalcogenide or trichalcogenide,    -   sulfide, selenide, or telluride of a transition metal;    -   boron nitride, or    -   a combination thereof, inclusive of molten Li metal interspersed        therein to provide a source for Li ions upon dissociation during        normal electrochemical cell discharge-charge cycles, etc.

-   The nanodiscs, nanoplatelets, nano-coating, or nano sheets can have    a thickness less than 100 nm. In other examples, the nanoplatelets    can have a thickness less than 10 nm and/or a length, width, or    diameter less than 5 μm.    Producing an Anode or Cathode Created from the Carbon Structures

Example processes for producing a three-dimensional (3D) carbon-basedelectrode, such as that created from lithiated carbon scaffold 400A, caninclude depositing, such as from one or more plasma-based thermalreactors or torches, in which thermal energy is propagated through aplasma and/or feedstock material supplied in a gaseous state,carbon-based particles 100A or 400A to form a first contiguous filmlayer, such as layer 406A shown in FIG. 4A, on a substrate, where thefirst contiguous film layer is characterized by a first electricalconductivity. Each of the carbon-based particles comprises electricallyconductive three-dimensional (3D) aggregates or agglomerations ofgraphene sheets 101B. The aggregates are can be orthogonally fusedtogether to form open porous scaffold 102A to facilitate electricalconduction along and across contact points of the graphene sheets.

A porous arrangement formed in open porous scaffold 102A, where theporous arrangement is conducive to receive electrolyte dispersed thereinfor Li ion transport through interconnected pores, such as hierarchicalpores 101A and/or the contiguous microstructures 107E, that define thediffusion pathways 109E. The first contiguous film layer has an averagethickness no greater than approximately 100-200 μm. In an example, abinder material is combined with graphene sheets 101B to retain graphenesheets 101B in a desired position to impart structure to open porousscaffold 102A. The binder may be or comprise a thermosetting resin or apolymerizable monomer, wherein curing the resin or polymerizing thepolymerizable monomer forms a solid resin or polymer with assistance ofheat, radiation, an initiator, a catalyst, or a combination thereof. Thebinder may be initially a polymer, coal tar pitch, petroleum pitch,mesa-phase pitch, or organic precursor material and is later thermallyconverted into a carbon material.

Additional quantities of the carbon-based particles 100A are depositedon the first contiguous film layer to form a second contiguous filmlayer there-upon, the second contiguous film layer having a secondelectrical conductivity lower than the first electrical conductivity,and being positioned closer to electrolyte 414A and away from thecurrent collector, which may be a sacrificial substrate. Li ion solutioncan be infiltrated into, such as by capillary infusion action, openporous scaffold 102A to react with exposed carbon on surfaces thereof tofacilitate Li ion dissociation and electric current supply, where theexposed carbon on the open porous scaffold can include a surface areagreater than approximately 100 m²/gm.

Carbon-based particles 100A and/or lithiated carbon scaffold 400A can besynthesized in-flight in a microwave reactor, or deposited in abottom-up manner, referring to a layer-by-layer deposition or growthwithin a thermal reactor, and may then be cast, via a liquid slurry tobe subsequently dried to form a carbon-based electrode that may besuitable for implementation or incorporation within a Li ion battery.Such a slurry may, in some examples, comprise chemical binders andconducting graphite, along with the electrochemically active innatecarbon.

The term hierarchical implies an arrangement of items in which the itemsare represented as being above, below, or at the same level as oneanother. Here, carbon-based particle 100A and/or lithiated carbonscaffold 400A may be grown by layer-by-layer deposition in a thermalreactor to create one or more grades, as indicated by film layers 406Ato 412A of the conductive particles 100A, 302B and/or 402A, referring tothat created by specific control of electrical, referring to contactpoints of graphene sheets 101B, and ionic, referring to the diffusionpathways 109E, conducting gradients throughout the thickness oflithiated carbon scaffold 400A. Tuning of each individually depositedlayer 406A through 412A results in relatively higher electricalconductivity at the current collector interface, and progressive lowerelectrical conductivity moving outwardly therefrom.

The graphene sheets 101B within carbon-based particle 100A can serve asboth electrical conductors, by conducting electric current throughcontact points and/or regions, and as active Li intercalating structuresto provide a source for the specific capacity of the anode electrode at744-1,116 mAh/g, such as 2 to 3 times that otherwise available fromconventional graphite anodes at 372 mAh/g. As a result, interconnected3D bundles of graphene sheets 102 within the carbon-based particle 100Amay be considered as nanoscale electrodes that concurrently enable arelatively high-volume fraction of electrolytically active materialalong with efficient, 3D interpenetrating, ion, and electron pathways.

This unique 3D structure of the carbon-based particle 100A enables bothstorage of electric charge at its exposed surfaces via capacitive chargestorage for desirable high-power delivery, relative to conventionalapplications, and also provides faradaic redox ions within the bulkthereof for desirable high electric energy storage. Redox, as generallyunderstood and as referred to herein, refers to reduction-oxidationreactions in which the oxidation states of atoms are changed involvingthe transfer of electrons between chemical species, most often with onespecies undergoing oxidation while another species undergoes reduction.

Faradaic, as generally understood and as referred to herein, refers to aheterogeneous charge-transfer reaction occurring at the surface of anelectrode, prepared with, and/or otherwise incorporating carbon-basedparticle 100A. For instance, pseudocapacitors store electrical energyfaradaically by electron charge transfer between electrode andelectrolyte. This is accomplished through electrosorption, redoxreactions, and intercalation processes, termed pseudocapacitance.

Roll-to-Roll Processing for Producing an Electrochemical Cell ElectrodeCreated from the Carbon Scaffold

Regarding manufacturing, lithiated carbon scaffold 400A can bemanufactured, to fabricate and/or build electrochemical cell electrodes,such as cathodes and/or anodes, in large-scale quantities by sequential,layer-by-layer, such as layers 406A through 412A shown in FIG. 4A,deposition of concentrations of carbon-based particle 100A and/or 100Eonto a moving substrate, such as a current collector, through aroll-to-roll (R2R) production approach. By consolidating 3D carbonscaffold structures directly out microwave reactors, analogous toexiting plasma spray processes, electrode films can be continuouslyproduced without the need for toxic solvents and binders that areotherwise used in slurry cast processes for battery electrodes.Therefore, battery electrodes employing lithiated carbon scaffold 400Amay be more readily produced with controlled electrical, ionic, andchemical concentration gradients due to the layer-by-layer, sequentialparticle deposition capabilities of a plasma-spray type processes; and,specific elements, such as dopants, can also be introduced at differentstages within the plasma deposition process.

Also, due to the pores 105E and/or the contiguous microstructures 107Einterspersed throughout carbon-based particle 100A, lithiated carbonscaffold 400A may be manufactured in a manner such that it isgravimetrically, referring to a set of methods used in analyticalchemistry for the quantitative determination of an analyte based on itsmass, superior to known devices. That is, carbon-based particle 100A,with pores and/or voids defined throughout 3D bundles of graphene sheets102 and/or conductive carbon particles 104, may be lighter thancomparable battery electrodes without a mesoporous structure includingvarious pores and/or voids, etc.

Carbon-based particle 100A may feature a ratio of active material toinactive material that is superior relative to conventionaltechnologies, in that greater quantities of active material areavailable and prepared for electricity conduction there-through relativeto inactive and/or structural reinforcement material. Such structuralreinforcement material, although involved in defining a generalstructure of carbon-based particle 100A, may not be involved or asinvolved in electrically conductive interconnected agglomerations ofgraphene sheets 101B. Accordingly, due to its high active material toinactive material ratio, carbon-based particle 100A may demonstratesuperior electrical conductivity properties relative to conventionalbatteries, as well as being significantly lighter than such conventionalbatteries given that carbon may be used to replace traditionally usedheavier metals. Therefore, carbon-based particle 100A may be particularwell-suited for demanding end-use application areas that also maybenefit from its relatively light weight, automobiles, light trucks,etc.

Carbon-based particle 100A may be created to rely electricallyconductive interconnected agglomerations of graphene sheets 101B toobtain a percolation threshold, referring to a mathematical concept inpercolation theory that describes the formation of long-rangeconnectivity in random systems. Below the threshold a giant connectedcomponent does not exist, while above it, there exists a giant componentof the order of system size. Accordingly, 3D bundles of grapheneelectrically conductive interconnected agglomerations of graphene sheets101B may conduct electricity from the current collector, as shown inFIG. 4A, toward electrolyte 414A.

Roll-to-Roll (R2R) Plasma Spray Torch Deposition System

As a variation from the presently disclosed atmospheric MW plasmareactor used to produce particle-based output including integrated,contiguous 3D hierarchical carbon scaffold films, a spray torchconfiguration can be employed to produce similar such carbon-basedstructures, such as that shown by roll-to-roll (R2R) system 400B. Plasmatorches permit for materials to be initially formulated, similar towaveguided reactor, then accelerated into an impact zone on a substratesurface that can be either moving or stationary. Each zone of the R2Rprocess can provide for unique control of dissimilar mixed phase orcomposite material synthesis, formulation, consolidation, andintegration, such as densification.

The plasma torch can be used to deposit carbon-based particles on acontinuous, moving substrate to enable an additive type process controlat locations of hot plasma jets depositing the carbon-based particlesand beyond the plasma afterglow region up to the impact zone of thesubstrate. Various properties can be controlled, such as defect density,residual stress, through control of deposition thicknesses of filmlayers, chemical and thermal gradients, phase transformations, andanisotropy. For electrochemical cell electrode fabrication, not only canthe atmospheric MW plasma torch create formulated and integratedcontinuous 3D graphene films without the need for toxic solvents such asNMP and or use of binders in accordance with conventional slurry castingprocess, but the plasma torch can be used to create integratedelectrode/current collector film structures for enhanced performance ata reduced cost.

FIG. 4B shows a roll-to-roll (R2R) system 400B employing an examplearrangement of a group 444B of plasma spray torches 422B through 428B,such as 422B, 424B, 426B, and/or 428B, all of which are configured toperform layer-by-layer deposition to fabricate, otherwise referred to asgrowing, the carbon-based scaffold 300B, shown in FIG. 3B, and/orvariants thereof, incrementally. Group 444B of plasma spray torches 414Bthrough 420B are oriented in a continuous sequence above the R2Rprocessing apparatus 440B, which, may include wheels and/or rollers 434Band 439B configured to rotate in the same direction, 430B and 432B,respectively, to result in translated forward motion 436B of sacrificiallayer 402B upon which layers 442B of carbon scaffold 436B may bedeposited in a layer-by-layer manner to achieve a graded electricalconduction gradient proportionate to the concentration level ofcarbon-based particles 100A contained per unit volume area in eachprogressive deposited layer, such as film layers 406A-412A.

Such deposition may involve the positioning of group 444B of plasmaspray torches 414B through 420B as shown in FIG. 4B, with an initial, indirection of forward motion 436B, spray torch 414B extending thefurthest in a downward direction, toward sacrificial layer 404B fromfeedstock supply line 412B, positioned to spray 422B carbon-basedmaterial to deposit initial layer 404B, also may be shown as interimlayer 406A in FIG. 4A, and so on and so forth, of carbon scaffold 300Bon sacrificial layer 402B. Initial layer 404B may be deposited toachieve the highest conductivity values, with each of the subsequentlayers 406B through 410B featuring a proportionately less-densedispersion of carbon-based particle 100A composing carbon-based scaffold300B to achieve a graded electric gradient for layers 442B.

That is, plasma spray torches 414B through 420B may be oriented to haveincrementally decreasing, or otherwise varying, heights as shown in FIG.4B, such that each spray torch from group 444B may be tuned to spray,from spray 422B to 428B, respectively, sprays of carbon-based feedstockmaterial supplied by feedstock supply line 412B. Accordingly, batteryelectrodes can be more readily produced with controlled electrical,ionic, and chemical concentration gradients due to the layer-by-layer,sequential deposition described herein with connection to plasmaspray-torch system 400B, which presents desirable features of plasmaspray type processes; and, specific elements or additional ingredientscan also be introduced at different stages within the plasma-based spraydeposition process described by plasma spray-torch system 400B. Suchcontrol may, extend to tunability of plasma spray-torch system 400B toachieve target electric field and/or electromagnetic field properties ofany one or more of layers 442B.

Group 444B of plasma spray torches 414B through 420B may employplasma-based thermally enhanced carbon spraying techniques to providecarbon coating processes in which melted or heated materials are sprayedonto a surface. The feedstock, coating precursor, is heated byelectrical, plasma or arc. or chemical means, such as a combustionand/or a flame.

Thermal spraying by plasma spray torches 414B through 420B can providethick coatings of approximately a thickness in the range of 20 μm ormore to several mm, depending on the process and feedstock, over a largearea at high deposition rate as compared to other coating processes suchas electroplating, physical and chemical vapor deposition. Coatingmaterials available for thermal spraying include metals, alloys,ceramics, plastics, and composites. They are fed in powder or wire form,heated to a molten or semi-molten state, and accelerated towardssubstrates in the form of μm-size particles. Combustion or electricalarc discharge is usually used as the source of energy for thermalspraying. Resulting coatings are made by the accumulation of numeroussprayed particles. The surface may not heat up significantly, allowingthe coating of flammable substances.

Coating quality is usually assessed by measuring its porosity, oxidecontent, macro and micro-hardness, bond strength and surface roughness.Generally, the coating quality increases with increasing particlevelocities.

Carbon Scaffold Implemented in a Li S Secondary Battery

Group 444B of plasma spray torches 414B through 420B may be configuredor tuned to spray carbon-based material in a controlled manner toachieve specific desired hierarchical and organized structures, such asopen porous scaffold 102A of carbon-based particle 100A and/or 100E withthe contiguous microstructures 107E suitable to be used for Li ioninfiltration via capillary action therein dependant on percentageporosity of carbon-based particle 100A and/or 100D. Total quantities ofS able to be infused into the contiguous microstructures 107E and/ordeposited on exposed surface regions of carbon-based particle 100Aand/or 100D, and other such similar structures. may depend on thepercentage porosity thereof as well, where 3D fractal-shaped structuresproviding larger pores, such as pores 105E, each having dimension 103Ecan efficiently accommodate and micro-confine S for desired time-framesduring electrochemical cell operation. Examples exist permitting for thecombination of S to prevent any resultant polysulfides (PS) migratingout of pores 105E purely by designing and growing structural S, withconfinement of S being targeted at a defined percentage, such as: 0-5%,0-10%, 0-30%, 0-40%, 0-50%, 0-60%, 0-70%, 0-80%, 0-90%, and/or 0-100%,any one or more of such ranges successfully showing of retardation ofpolysulfide migration out of the electrode structure.

Carbon Scaffold Implemented in a Li Air Secondary Battery

Existent Li air cathodes may last only 3-10 cycles, and thus have notyet been universally understood to provide very promising or reliabletechnologies. In such cathodes, air itself acts as the cathode,therefore the reliable and robust supply of air flowing through thecathode, such as through pores, orifices, or other openings, effectivelycurrently precludes realistic applications in consumer grade portableelectronic devices such as smartphones.

Devices can be made with some sort of air pump mechanism, but airpurification remains an issue, given that any amount of impurityprevalent in the air can and will react with available Li in parasiticside-reactions ultimately degrading specific capacity of the overallelectrochemical cell. Moreover, air only provides only about 20.9% O₂,and thus is not as efficient as other alternative current advancedbattery technologies.

Nevertheless, even in view of the above-mentioned challenges, examplesprovided above relating to carbon-based particle 100A, 100D and/or anyvariants thereof implemented in carbon scaffold 300B and/or lithiatedcarbon scaffold 400A can be configured to function in a 3D-printedbattery. Notably, measures can be taken to guard against, such as bytuning to achieve desirable structural reinforcement in certain targetedareas of open porous scaffold 102A, to prevent against unwanted and/orsudden collapse of porous structures, such as to create clogging ofpassageways defined therein. In example, carbon scaffold 300B can bedecorated with a myriad of metal oxides to achieve such reinforcement,which may also control or otherwise positive contribute to mechanicaltunnelling of the structure itself once lithium reacts with air tospontaneously form a solid from that state, etc. Traditionalcircumstances, such as absent special preparations undertaken regardingimplementation of the disclosed carbon-based particle 100A and/or thelike with Li air cathodes can otherwise involve Li ions reacting withcarbon provided in a gaseous state, such that the Li ion and thecarbon-containing gas react to form a solid that expands. And, dependingon where this expansion occurs, can mechanically degrade the overallcarbon-based mesoporous scaffold structure, such as of carbon scaffold300B.

Preparation for Lithiation of Carbon-Based Particles

To enable alternative non-Li or lithiated carbon-based scaffoldedcathodes, such as those confining sulfur, oxygen, and vanadium oxide,over current lithium oxide compound cathodes, as well as to accommodatefirst charge lithium loss, resulting reduced coulombic efficiency, incurrent Li ion cells, a scalable pre-lithiation method for carbon-basedstructured intended for implementation in electrochemical cellelectrodes may be required. As a result, various experimental attemptshave been conducted with carbon-based particle 100A, 100D and/or anyderivative structures based therefrom, including carbon scaffold 300Bsuch as ball milling, post thermal annealing, and electrochemicalreduction from an additional electrode. Such efforts have been used topre-lithiate, such as chemically preparing a carbon-based structure toreact with and/or confine lithium physically and/or chemically, but havemet with uniformity, lithium reactivity, costs, and scalabilitychallenges.

Nevertheless, by fine-tuning reactor process parameters, carbon-basedparticle 100A, 100D, and/or carbon scaffold 300B may be synthesizedand/or fabricated by layer-by-layer deposition process, as substantiallydiscussed earlier, to serve as a carbon-based host structure withengineered surface chemistry, such as including nitrogen and oxygendoping to facilitate rapid decomposition involving disproportionation ofoxides.

Upon thermal activation, which can include the formation of one or moresparks, Li metal can be spontaneously, such as without a pressuregradient and non-reactively infiltrated driven by capillary forces tocreate a controlled, pre-lithiated carbon structure or particle buildingblocks. Subsequently, such pre-lithiated particle building blocks can besynthesized into an integrated composite film with graded electricalconductivity from:

-   -   a high conductivity at a back plane in contact with the current        collector, such as shown by interim layer 406A, to    -   an insulated ion conducting layer at the electrolyte/electrode        plane.

-   Surface chemistry, as may be related to non-reactive infiltration of    Li metal can be tuned by optimizing oxide thermal reduction degree,    such as an exotherm, by using thermogravimetric analysis (TGA) or    differential scanning calorimetry DSC analytical techniques.

To address scalability concerns as may be related to transitioning froma low-volume laboratory testing and sample production environment, to ahigh-volume large-scale plant capable of fulfilling multiple customerorders simultaneously, the above described pre-lithiation process isreadily adaptable to a continuous roll-to-roll (R2R) format, analogousto other liquid melt wetting processes such as brazing.

Thin film Li clad foil, which can in some configurations includetantalum (Ta) or copper (Cu), can be loaded onto a heated calendaringroll, to be brought into contact with carbon-based particle 100A, orcarbon film, in the case of the spray torch process, in a controlledthermal, dry environment. Thermal residence, such as soak, time,gradient, and applied pressure can adjust and controlled to facilitateboth: (1) activation; and, (2) infiltration process steps.

Initiation of Lithiation of the Carbon Scaffold

Prior to the development of Li metal infusion methods into carbon-basedstructures and/or agglomerate particles, efforts have been undertaken toassess the following two scenarios:

-   -   growing microwave graphene sheets that have extended D-spacing        that would allow Li intercalation to occur in-between individual        graphene sheets at a much more efficient or a faster rate than        what would occur in typical, commercially-available, graphene        sheets; and, growing FLG in such a way to successfully and        repeatably achieve such higher de-spacing; and    -   using a wet liquid Li metal front that propagates into the        hierarchical pores 101A and/or the contiguous microstructures        107E defined by open porous scaffold 102A of carbon-based        particle 100A and/or 100D, where attraction from Li metal to        exposed carbon-based surfaces to wet the same relative to        otherwise functionalizing exposed carbon-based surfaces.

-   The presently disclosed thermal reactors can perform post processing    to create highly organized and structured carbons that have that    functioning relating to the infiltration of molten Li metal and/or    other species, such as infiltration of aluminum into a silicon    carbide-sintered material, and hammering the surface of the    particles to promote infiltration of a molten (Li) metal front    without additional pressure from outside sources. Such efforts    permit for continuous wetting instead of using capillary pressure to    push metal into open porous scaffold 102A of carbon-based particle    100A and/or 100D.

FIG. 4A shows a lithiated carbon scaffold formed from severalinterconnected carbon-based particles 402A, similar in form and functionto carbon-based particles 100A and/or 100E, synthesized and deposited atvarying concentration levels in the film layers 406A to 412A, from mostconcentrated to least concentrated. All of the film layers 406A through412A, are configured to be infiltrated, via non-reactive capillaryinfusion methods, with a molten Li metal and/or Li ion solution inliquid state or phase for intercalation of Li ions in-between pairs ofgraphene sheets of the graphene sheets 101B. Example D-spacing ofapproximately 1 Å to 3 Å can be targeted during synthesis of thegraphene sheets 101B to retain more Li ions between alternating graphenesheets than conventional graphene sheet stacks.

Voids 416A, referring to vacant regions or spaces, between adjacentand/or contacting carbon-based particles 402A may be defined by asection of lithiated carbon scaffold 400A positioned away from a currentcollector 420A and facing a liquid-phase electrolyte layer, apassivation layer 418A. Passivation implies a material becoming passive,that is, less affected or corroded by the environment of future use. Inaddition, or in the alternative, a Li ion conduction insulating, orgraded interphase layer can be deposited on layer 412A, such as at thesame location of the passivation layer 418A, facing electrolyte 414A tominimize side reactions with free and/or physically and/or chemicallyunattached Li in ionic form.

Prior to the deposition or placement of any such encasing layer, Li, asprovided by molten Li metal, may be flowed in liquid state into thevoids 416A defined by the carbon-based particles 402A to assist informing electrochemical gradients proportionate to the level ofconcentration of carbon-based particles 402A in each layer of the filmlayers 406A-412A.

Repeated, or cyclical, Li ion electrode, such as the anode or thecathode, usage in secondary batteries can result in problems due tousage of molten Li metal, such as volume expansion during re-depositingin electroplating operations, implying a process that uses an electriccurrent to reduce dissolved metal cations so that they form a thincoherent metal coating on an electrode. The term can also be used forelectrical oxidation of anions on to a solid substrate, as in theformation of silver chloride on silver wire to makesilver/silver-chloride electrodes.

Processes used in electroplating with relation to infiltration of Li ionsolution into lithiated carbon scaffold 400A may be referred to aselectrodeposition, also known as electrophoretic deposition (EPD), andis analogous to a concentration cell acting in reverse. Electroplating,as described above, with Li ions can result in a volume expansion on theorder of approximately 400% or more of lithiated carbon scaffold 400A.Such an expansion is undesirable from a stability standpointmicro-mechanically and causes degradation with many dead zones,referring to inactive or non-chemically and/or electrically activatedregions, therefore ultimately preventing the derivation of longerlifespans out of so-equipped Li ion batteries. Generally, it isdesirable to have a majority of the Li ion material plate, meaningreduce onto a smooth and uniform surface to therefore facilitate uniformdeposition of Li ions. Removal will also be smooth in a smooth planarinterface.

In practice, Li, when infiltrated into the carbon scaffold 400A may tendto form unwanted dendrites, defined as crystals that develop with atypical multi-branching tree-like form. Such Li ion dendrites, also inthe form of acicular Li ion dendrites, acicular describing a crystalhabit composed of slender, needle-like crystal deposits, grow away fromsurfaces upon which Li ions are infiltrated, such as upon and/orin-between individual graphene sheets 101B. In some circumstances, withenough battery charge-discharge cycling, a dendritic protrusion orprotuberance can grow across all the way through from an anodeincorporating the lithiated carbon based scaffold 400A to a cathodepositioned opposite to the carbon based scaffold within anelectrochemical cell to cause a short route or circuit, describing whenthere is a low resistance connection between two conductors that aresupplying electrical power to a circuit. This may generate an excess ofvoltage streaming and cause excessive flow of current in the powersource. The electricity will flow through a short route and cause ashort circuit.

Capillary Li ion infusion techniques into lithiated carbon scaffold 400Acan address many of the described problems. Nevertheless, a persistentissue encountered in Li ion batteries includes that a conventionalcathode provides only a limited quantity of specific capacity or energycapability. Likewise, on the anode side, decreases have also beenobserved in specific capacity and energy density as well. Thus, even inview of how relatively desirable, in terms of electric energy storagecapacity and current delivery, a Li ion battery may be compared to Limetal hydride or lead-acid, or Ni Cad batteries, even greateradvancements in electric power storage and delivery are possible,regarding the protection against or prevention of unwanted Li-baseddendritic formations, upon the incorporation of any one or more of thepresently disclosed carbon-based materials, such as the lithiatedcarbon-based scaffold 400A, to approach the theoretic capacity of pureLi metal, which has a specific capacity of around 3,800 mAh/g.

Other approaches have been undertaken including the development ofsolid-state batteries, describing no liquid phases at all. However,attention has returned to Li metal, due to oxide electrolyte being usedto achieve and stabilize contact with Li. And, alternatives to Li metalhave also been explored including Si, Sn, and various other alloys.However, even upon elimination of Li metal, a Li ion source may still berequired.

Alternative-to-lithium materials in a Li ion battery electrode structuremay yield the following energy density values: oxides provide 260 mAh/g;and, sulfur (S) provides 650 mAh/g. Due to its relatively high energydensity capabilities, it is desirable in battery electrode applicationsto confine sulfur (S), so it is not solubilized or dissolved intosurrounding electrolyte. To that effect, sulfur micro-confinement isneeded, as described earlier in relation to the pores 105E of thecontiguous microstructures 107E of, as shown in FIG. 1E, of the openporous scaffold 102A. A confined (or micro-confined liquid implies aliquid that is subject to geometric constraints on a nanoscopic scale sothat most molecules are close enough to an interface to sense somedifference from standard bulk conditions. Typical examples are liquidsin porous media or liquids in solvation shells.

Confinement, and/or micro-confinement, referring to confinement withinmicroscopic-sized regions regularly prevents crystallization, whichenables liquids to be supercooled below their homogenous nucleationtemperature even if this is impossible in the bulk state. Thus, in viewof the various challenges presented above, and others not discussedhere, various improvements to traditional graphite-based anodes may beachieved by instead employing few layer graphene (FLG) materials and/orstructures, defined as having less than 15 layers of graphene grown,deposited or otherwise organized in a stacked architecture with Li ionsintercalated there-between at defined interval and/or concentrationlevels. Any one or more of carbon-based particle 100A, 100D and/or thelike may be so prepared.

Doing so, going from graphite to FLG, may improve specific capacity fromapproximately 380 to over a 1,000 mAh/g for Li-intercalated carbon-basedstructures. Disclosed materials can replace graphite with FLG to permitfor a higher active surface area and can increase spacing in-betweenindividual graphene layers for infiltration of up to 2 to 3 Li ions, asopposed to just 1 Li ion as commonly may be found elsewhere, as shown byFIG. 1I indicating that the various graphite or graphene layer planescan be controlled, in terms of D-spacing, to achieve various fitments ofLi ions in-between adjacent graphite or graphene layer planes.

In graphene, hexagonal carbon structures in each graphene sheet may staypositioned on top of each other, this is referred to as an A-A packingsequence instead of an A-B packing sequence. An example carbon packingsequence is shown in the chemical structural diagram shown in FIG. 1G,where Li ions can fit in void spaces defined by carbon atoms arrangedand bonded in a hexagonal lattice structure. Particularly,configurations are envisioned for graphene sheets and/or few-layergraphene (FLG) where individual layers of graphene may be stackeddirectly on top of each other to obtain incommensurate, disproportionateand/or otherwise irregular, stacking as shown by Stage 3 in FIG. 1H,which in turn permits for the intercalation of addition Li ionsin-between each graphene layer of FLG structures.

Under traditional conditions and circumstances, the insertion of Li ionsfrom, the top-down or bottom-up in layered graphene structures may proveexceedingly difficult in practice. Comparably, Li ions more easilyinsert in-between individual graphene layers separated by a definabledistance. Thus, the key is to manage and tune exactly how much edge areais available. In that regard, any of the carbon-based structureddisclosed herein are so tunable. And, carbon in graphene is alsoconductive—therefore, this feature provides for dual-roles by: (1)providing structural definition to FLG scaffold electrode structures,such as carbon scaffold 300B and/or lithiated carbon scaffold 400A; (2)and, conductive pathways therein.

Production techniques employed to fabricate any one or more of thecarbon-based structures disclosed herein may indicate a desirability ofadjustment of individual graphene-layer edge lengths relative to planarsurfaces thereof; also, the adjustment of the spacing in betweenindividual graphene stacks may be possible. Graphene, given itstwo-dimensional structure, necessarily provides significantly moresurface area in which Li ions can be inserted. Thus, applying graphenesheets in accordance with various aspects of the subject matterdisclosed herein may provide a natural evolution in the direction ofenhanced energy storage density.

Individual graphene sheets are held in position as a part of the plasmagrowth process. Carbon based gumball-like structures are self-assembledin-flight as described earlier from FLG and/or combinations of to formparticles, such as carbon-based particle 100A, 100D, 402A and/or thelike, with a defined long-range order defined as where solid carbonmaterials demonstrate a crystalline phase structure. Once the positionsof carbon atom and its neighbors are defined, the location of eachcarbon atom can be defined precisely throughout the crystalline phasestructure such that smaller structures agglomerate to form essentiallywhat resembles a gumball.

Size dimensions of such gumball-like structures, describing individualcarbon-based particles 100A and/or the like, may be on the order of 100nm across at their respective widest points. Larger agglomeratedparticles forming a carbon lattice structure 1800 as shown in FIG. 18can be made up from multiple gumball-like structures may be an order ofmagnitude larger, about 20-30 microns in diameter and provide structuraldefinition to one or more of the film layers 406A-412A shown in FIG. 4A.

In contrast, traditional battery electrode production methods typicallyemploy known deposition techniques such as chemical vapor deposition(CVD) or other fabrication techniques, nanotubes, etc., to growstructures off of a defined fixed substrate or surface, and thus do notinvolve the in-flight fusing of carbon-based particles in asubstantially atmospheric vapor flow stream of a carbon-containinggaseous species as disclosed herein. Such known assembly processes andprocedures can tend to be very labor intensive, and they may also permitfor the growth of structures of limited thickness, 200-300 microns inthickness.

Graphene-on-graphene densification of multiple FLG on an originalgumball-based carbon scaffold, such as the carbon-based particles 100A,the carbon scaffold 300B, the lithiated carbon scaffold 400A, and/or thelike may also result in increased energy density and capacity. Suchdensification in target regions of the carbon scaffold may also beperformed or otherwise accomplished after creation of a largeragglomerated particle comprising multiple carbon-based particles 100A.Generally, Li ions may be plated onto electrode prior to reduction,therefore Li ion may transition from an ion to a metal state dependenton battery chemistry. Moreover, in an implementation, similar toelectroplating, graphene may be grown in a stacked manner on othermaterials, such as plastic, and tuned to obtain a desirable brightand/or smooth finish. Such electroplating processes are reversible andmay include separate but interrelated plating process and a strippingprocesses, intended to place the Li ions and/or atoms down and for thesubsequent removal thereof.

In continual cyclical use of secondary Li ion batteries, involvingmultiple charge-discharge-recharge cycles, surfaces upon whichcarbon-based structures are grown and/or built may eventually roughenedand therefore susceptible to or accommodative of unwanted dendritegrowth. In contrast, techniques employed to produce carbon-basedparticles 100A and/or the like, as discussed above, substantiallyprevent such dendrites from growing, enabled by the usage of Li metalsubstantially free of impurities along with carbon-based graphenestructures to enable high specific capacity values.

Usage of graphene sheets permits for relatively greater exposed surfacearea available for plating or intercalating operations for theinfiltration referring to non-reactive capillary infusion of Li ions.Thus, any tendency to go to a certain point anymore is removed; and,fundamentally the way plating and stripping occurs may be changed due tothe graphene having a higher surface-area to volume ratio than otherconventional carbon-based materials such as graphite. Li ions may beintroduced at least partially relying upon liquid Li; however, givenLi's predisposition for chemical reactivity with surrounding and/orambient elements, water-based moisture and oxygen must be kept away.Similarly, the introduction of impurities results in deleteriouseffects. Metal-matrix composites have been studied, in relation to thedisclosed carbon-based structures, regarding usage of Li metallicallybonding or otherwise forming a metal-matrix composite with C, thereforeoffering additional options regarding the fine-tunability and managementof reactivity at exposed surfaces.

Li in contact with C may result in circumstances where the free energyof carbide of Li at contact surfaces must be suppressed and/orcontrolled to avoid unwanted reactivity related to spontaneous Liinfiltration in carbon-based particle 100A and/or the like.Traditionally, Li, in a liquid phase, typically forms carbonates andother formations due to the chemistry of the electrolyte. However, whatis proposed by the present examples relates to the creation of arelatively stable solid electrolyte interface (SEI) prior to theintroduction of the liquid electrolyte.

Moreover, multiple methods and/or processes to affect Li ion interfaceareas may be available. For instance, preparing the surface of liquid Liby alloying with Si and other elements will reduce the reactivity andpromote overall Li ion wetting of larger agglomerated particles, eachcomprising multiple carbon-based particles 100A. In an example,approximately less than 1.5% of Li was observed to have preferentiallymoved to exposed surfaces, exposed to the electrolyte.

3D Hierarchical Graphene with Increased Specific Capacity (˜3×) OverConventional Graphite Anodes

Commercial use of graphitic carbon materials for anode active materialsas well as fine carbon black materials for electrical conduction isjustified by their relatively low cost, excellent structural integrityfor the insertion and extraction of Li+ ions, safety free from Lidendrite formation, and formation of a protective passivation layeragainst many electrolytes such as that associated with the formation orbuild-up of the solid electrolyte interphase (SEI).

The low specific capacity of graphite at 372 mAh/g, havingstoichiometric formula—LiC₆, however, is a critical limitation and as aresult, can potentially hinder the advance of large-scale energy storagesystems that demand high energy and power densities. By designing andapplying a three-dimensional (3D) graphene with intercalated Li and/or Scompounds electrode approach as disclosed herein by any one or more ofthe aforementioned Figures, a larger loading amount of active anodematerials can be accommodated while facilitating Li ion diffusion.Further, 3D nanocarbon frameworks, such as that defined by open porousscaffold 102A and/or the like) can impart:

-   -   an electrically conducting pathway; and    -   structural buffer to high-capacity non-carbon nanomaterials,        which results in enhanced Li ion storage capacity.

-   Both (1) and (2) enhance Li ion storage capacity (>1,000 mAh/g) and    enhanced cycling (stability) performance can be achieved with these    3D structures.    Integration with Li Ion (and Li S) Battery Electrode

An example Li ion, or Li S, secondary electrochemical cell system 500 isshown in FIG. 5, having an anode 501 and cathode 502 separated by aseparator 517. Any one or more of the anode 501 and the cathode 502 canbe substantially formed by the lithiated carbon scaffold 400A shown inFIG. 4A, and represented here in a simplified representation of largerand smaller carbon particles 509, all of which are at least partiallyconfine Li ion-conducting electrolyte solution 518 containingdissociated Li ion conducting salts 505 as shown. The separator, aporous membrane to electrically isolate the anode 501 and the cathode502 from each other, is also in the position showed. Single Li ionsmigrate through pathway 507 back and forth between the electrodes of theLi ion-battery during discharge-charge cycles and are intercalated intocarbon-based active materials forming any one or more of the anode 501and the cathode 502 for confinement therein as necessary for optimalsecondary electrochemical cell 500 performance.

Electrolytes, such as the electrolyte solution 518, can be generallycategorized into several broad categories, including liquid electrolytesand solid electrolytes. The liquid electrolyte is most commonly usedelectrolyte system across many conventional batteries due to its highionic conductivity, low surface tension, low interface impedance, andgood wettability within the electrode. In Li S battery systems, liquidelectrolytes dominate because they help compensate for a lot of thepotentially encountered poor electrochemical kinetics of S and lithiumsulfide (Li₂S). In Li S systems, a liquid electrolyte containing anether-based solvent can be used, since because ether-based solvents,unlike carbonates, do not negatively react with S and generally havebetter Li ionic transport properties. A potential drawback of usingether-based electrolytes includes solubility of long chain polysulfides(PS), which can eventually lead to Li S electrochemical cell degradationdue to PS shuttle, migration, and volumetric expansion of the cathodeleading to compromise of its structural integrity.

Outside of conventional liquid-phase electrolytes, solid stateelectrolytes can be potentially configured to stop formation and growthof Li dendrites, and to stop the PS shuttle as solid state electrolyteseffectively convert Li S systems from a multi-phase system to asingle-phase system, resulting in no internal shorting, no leakage ofelectrolytes, and non-flammability. Solid polymer electrolytes can bedefined as a porous membrane possessing the ability to transport Li ionsacross that membrane. A solid electrolyte can be further categorizedinto solid polymer electrolytes, gel polymer electrolytes, andnon-polymer electrolytes. A solid polymer electrolytes can be composedof a lithium salt dissolved in a high molecular weight polymer host.Common polymer hosts used are polyethylene glycol (PEO), polyvinylidenefluoride or polyvinylidene difluoride (PVDF), poly(p-phenylene oxide) orpoly (PPO), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP),and poly(methyl methacrylate) (PMMA), etc.

Gel polymer electrolytes can be similar to solid polymer electrolytes inthat they have a high molecular weight polymer, but also include aliquid component tightly trapped within the polymer matrix. Gel polymerelectrolytes, in some implementations, were developed to compensate forpoor ionic conductivity observed in solid polymer electrolytes. Overother forms of solid electrolytes, non-polymer solid electrolytes haveadvantages of high thermal and chemical stability.

Non-polymer solid electrolytes consist of a ceramic and commonly foundnon polymer electrolytes include LIthium Super Ionic CONductor(LISICON), Li₇La₃Zr₂O₁₂ (LLZO),Li₇La_(2.75)Ca_(0.25)Zr_(1.75)Nb_(0.25)O₁₂ (LLCZN), Garnet, and Ge-DopedLi_(0.33)La_(0.56)TiO₃ (Ge-LLTO) Perovskite, etc., and can have athickness in a range of approximately 0.5 μm to 40 μm, which can beconfigured to substantially prevent any one or more of Li dendriteformation or growth. Nevertheless, some solid electrolytes can sufferfrom certain challenges including relatively poor Li ionic conductivityand weight. At the thicknesses needed to prevent Li dendrite growth,observed ionic impedance can so high that a so-equipped Li ion or Li Sbattery may not function as desired, while at the thicknesses needed tohave acceptable Li ionic conductivities, Li dendrite growth may not beprevented.

During discharging, Li is deintercalated from the anode 501. The activematerials of the cathode 502 can include mixed oxides. Active materialsof the anode 501 can include primarily graphite and amorphous carboncompounds including those presented herein. These are the materials intowhich the Li is intercalated.

The Li ion conducting salt 505 can dissociate to provide mobile Li ionsavailable for intercalation into any one or more of the uniquecarbon-based structures disclosed herein that can be incorporated intoany or more of the anode 501 or the cathode 502 as a formative materialto achieve specific capacity retention capability exceeding 1,100 mAh/gor more as facilitated by the contiguous microstructures 107E. Li ionsform complexes and/or compounds with S in Li S systems and aretemporarily confined during charge-discharge cycles at levels nototherwise achievable through conventional unorganized carbon structuresthat require adhesive definition and combination via a binder, which canas discussed earlier also inhibit overall battery performance andlongevity.

The pores 105E of the contiguous microstructures 107E shown in FIG. 1E,which may form the carbon based particle 100A, 100D, 402A and/or thelike and be used to produce conductive graded film layers for any one ormore of the anode 501 or the cathode 502 can be defined, duringsynthesis, to include a micropore volume (pores<1.5 nm). Sulfur (S) isinfused via capillary force into the pores 105E where the S is beconfined. Successful microconfinement of sulfur would prevent dissolvedpolysulfides (PS), as presented earlier regarding Li S systemsgenerally, from reprecipitating outside of their original pores. Toachieve an active carbon composite capable of holding achievablequantities of S, a pore volume of 1.7 cc/g with all 1.7 cc/g attributedto pores with an opening<1.5 nm may be needed.

Operationally, in either Li ion or Li S systems, Li ions migrate fromthe anode 501 through the electrolyte 518 and the separator 517 to thecathode 502. Here, molten Li metal 514 micro-confined, as shown inenlarged areas 516 and 513, within few-layer graphene sheets 515associated with any of the presently disclosed carbon-based structuresused as formative materials for the anode 501 or the cathode 502. MoltenLi metal may dissociate in the anode 501 pursuant to the followingequation (8):

FLG-Li→FLG+Li+e−  (8)

Eq. (1) shows electrons 506 and 511 discharging 508 to power an externalload such that Li ions 512 migrating to cathode 502 return to athermodynamically favored position within a cobalt oxide-based latticepursuant to the following equation (9):

xLi⁺+xe⁻+Li_(1−x)CoO₂→LiCoO₂.

-   During charging, this process is reversed, where lithium ions 505    return-migrate from the cathode 502 through the electrolyte 518 and    the separator 517 to the anode 501.

Disclosed carbon-based structures, referring to the surprising favorablespecific capacity values made possible by the unique multi-modalhierarchical structures of carbon-based particle 100A, 100D and/orderivatives thereof, including carbon scaffold 300B and lithiated carbonscaffold 400A, any one or more of which can be configured to build upontraditional advantages offered by Li ion technology. Compared to sodiumor potassium ions, the relatively smaller Li ion exhibits asignificantly faster kinetics in the different oxidic cathode materials.Another difference includes that, as opposed to other alkaline metals,Li ions can intercalate and deintercalate reversibly in graphite andsilicon (Si). And, a lithiated graphite electrode enables higher cellvoltages. Disclosed carbon-based material therefore enhance the easethrough which Li ions can intercalate and deintercalate reversiblybetween graphene sheets, due to the unique lay-out of few-layer graphene(FLG), such as 5-15 layers of graphene in a generally horizontallystacked configuration 101C, as employed in carbon-based particle 100Aand/or the like, and are suitable for application hardcase, pouch cell,and prismatic applications.

Stabilization of Artificial Solid-Electrolyte Interface (SEI) Films byDoping

At present, current Li ion batteries form a protective passivation layer(such as the passivation layer 418A shown in FIG. 4A), or solidelectrolyte interface (SEI), at the electrode surface exposed toelectrolyte during a pre-conditioning step when the electrolyte is firstintroduced followed by initial discharge and charge steps. Althoughelectrolyte chemistry and pre-conditioning protocols, such ascharge/discharge rate and overvoltage, may be adjusted to optimize filmpassivation, referring to SEI formation, conventional film layersincorporated into electrodes can still be chemically and mechanicallyunstable.

Referring now to FIG. 6A, specific elements 602A may be introduced tothe aforementioned carbon materials 600A by doping. The elements 602A,such as silicon, sulfur, nitrogen, phosphorous at an example exposedelectrode surface 601A can be coated at specified levels of conformalcoverage onto the electrode surfaces 601A of the carbon structures, suchas ranging from sparse decoration to complete conformal coverage.Precedence for formation of stable solid-state electrolyte ionconducting layers have been reported in literature; referring tosulfide-based thioLISCONs, defined as Lithium Sulfur CONductors havingthe chemical formula Li_(3.25)Ge_(0.25)P_(0.75)S₄, and phosphate-basedNASCIONs, such as sodium (Na) Super Ionic CONductor, which usuallyrefers to a family of solids with the chemical formulaNa_(1+x)Zr₂Si_(x)P_(3−x)O₁₂, 0<x<3 and the acronym is also used forsimilar compounds where Na, Zr and/or Si are replaced by isovalentelements. The formation of a stabilizing solid state passivation layeras explained here include doping specific elements 602A the electrodesurface 601A can be engineered prior to battery assembly and therebydecouple the formation process of a stable solid state ion conductinglayer from the reduction/oxidation events that occur when in contactwith electrolyte, as encountered in current Li-ion battery fabricationwhich still often suffers from long term stable operation.

Manufacturing with Slurry Cast Techniques

In combination with conductive particles, such as carbon black, andoptionally polymer binders and solvent, such as NMP, any one or more ofthe tuned 3D hierarchical graphene-based particles disclosed herein canbe directly incorporated into conventional slurry cast electrodefabrication processes as follows:

-   -   an active graphene based (FLG) substitute for graphite        particles, in the case of the anode; and/or    -   infused with active sulfur (S) in the case of the cathode.

-   The 3D graphene particles provide high specific capacity graphene    building blocks with interconnected mesoporous ionic conducting    channels for rapid Li ion transport along with carbon black and    binder to ensure electrical conducting pathways, such as defined by    the graphene sheets 101B used as a formative material for the    contiguous microstructures 107E, which also provide mechanical    integrity.

Disclosed carbon materials can be pre-lithiated by ball milling and/orpost thermal annealing and electrochemical reduction from a thirdelectrode, at:

-   -   a relatively low concentration to offset first charge Li loss in        conventional oxide cathode cell; or    -   at a relatively higher concentration to increase overall        specific capacity for both oxide and alternative cathode        configurations, and then slurry cast into electrodes.

FIGS. 6B1 and 6B2 show a schematic diagrams comparing a chemicallynon-reactive system 600B1 against a chemically reactive system 600B2 inthe context of active material infiltration and confinement of lithium(Li) within the active material, according to some implementations.Although configurations where molten Li metal is infiltrated into anyone or more of the presently disclosed carbon-based structures shown inFIG. 1A through FIG. 1E, such as the contiguous microstructures 107E,alternative or additional implementations provide for the infusion ofmolten Li metal droplets, in a vapor phase, into pores, such as thepores 105E. In the chemically non-reactive system 600B1, Li metaldroplets are prepared, or are expected to, fail to react with carbon oncontact with exposed carbon surface due to, for example, Li-phobicity ofthe carbon. Regardless, infusion of vapor-phase Li droplets at anintrinsic contact angle (θ) between approximately 50° and 90° canprovide a balance between competing liquid-to-solid adhesive forces,such as adhesion observed between liquid-phase molten Li droplets (suchas that used to provide the Li ions 108E) and solid-phase carbonproportional to (γ_(sl)) cohesive forces in liquid (γ_(lv)).

Wetting, occurring between the vapor-phase Li and solid-phase carbon, isdefined as the ability of a liquid to maintain contact with a solidsurface, resulting from intermolecular interactions when the two arebrought together where the degree of wetting, or wettability, can bedetermined by a force balance between adhesive and cohesive forces.Desirable degrees of wetting can occur where adhesive energy is nearcohesive energy, such as with tightly-held bonds, as encountered inliquid-phase metals dispersed on solid-phase metals, or as seen insemiconductors including silicon (Si), germanium (Ge), or siliconcarbide (SiC), as well as ceramics including any one or more ofcarbides, nitrides, or borides, which can demonstrate metallic-likebehavior near exposed surfaces. And, usage of liquid-phase metals with arelatively high solubility for atmospheric contaminants, such as oxygen(O), nitrogen (N), or moisture (H₂O vapor), or carbon, can reduce thecontact angle observed or needed during wetting at contaminated solidsurfaces, or at pure-carbon surfaces.

In the chemically reactive system 600B2, wetting of a carbon surfacelayer 602B2, such as that encountered on surfaces of the carbon-basedparticle 100A exposed to Li metal, can be accompanied by chemicalreaction occurring at that interface, such as the dissolution of solidcarbon materials or the formation of a new 3D layer 604B2 or compoundinvolving at least partial consumption of the underlying carbon surfacelayer 604B2. The addition of dopants, tuned by type and concentration,at the carbon surface layer 602B2 can also affect a degree or extent ofwetting, as shown by the various fluid positions 606B2, 608B2 and 610B2,showing a molten Li droplet with very little wetting at position 606B2with progressively greater wetting at positions 608B2 and 610B2,respectively. The formation of the new 3D layer 604B2 can, in someimplementations, alter properties of the underlying carbon surface layer602B2, such properties including electrical conductivity, or canotherwise limit, by pinching off, infiltration into porous media by theformation of a volumetrically expanded reaction product, shown as thenew 3D layer 604B2.

For either the chemically non-reactive system 600B1 or the chemicallyreactive system 600B2, decreasing the contact angle of liquid Li metaldroplet beads, such as that shown in position 610B2, can promote wettingof the underlying carbon surface layer 602B2. And, for configurationswhere the carbon surface layer 602B2 incorporates adsorbed or chemicallybonded oxygen (O), the addition of elements, such as that also referredto as getters, with a high O solubility can reduce or otherwise controlO activity at the new 3D layer 604B2. For solid variants of the carbonsurface layer 602B2, the addition of elements such as nickel (Ni), iron(Fe), or others to liquid-phase metals having a high carbon solubilitycan insure a relatively high surface activity or affinity.

FIG. 7 shows an example process workflow where molten Li metal isinfiltrated into void spaces between carbon agglomerations to initiate areaction at exposed carbon surfaces, according to some implementations.Considerations for infiltrating Li metal 704, 706 into packed carbonscaffold 702, which may be incorporated within or otherwise provide aformative material for any one or more of the presently disclosedcarbon-based structures such as carbon particle 100A shown in FIG. 1A orcontiguous microstructures 107E shown in FIG. 1E, are shown in aninfiltration process workflow schematic 700. Surface conditions of thecarbon scaffold 702 can be tuned prior to infiltration by molten Limetal, which can enter into the carbon scaffold 702 by any one or moreof capillary infusion using molten Li metal in a liquid-phase, orinfusion of molten Li metal droplets suspended in air forming a Li metalvapor. Precise tuning of the following conditions at carbon scaffold 702surfaces exposed to incoming Li include control of:

-   -   atmospheric contaminants such as moisture (H₂O vapor), oxygen        (O), nitrogen (N), and hydrocarbons configured to confine or        contain physiosorbed or chemisorbed O;    -   formation of nitrogen bonds at surface during post plasma        treatment; and    -   purity of lithium metal, such as control of prevalent surface        oxides, nitrides, and carbonates.

Li infiltration can be initiated by capillary infusion of molten Limetal 704, 706 to intersperse within the carbon scaffold 702 as well asfill, forming a lithiated carbon compound 708, void spaces of the packedcarbon scaffold 702. Procedures can be followed by a non-reactive Liwetting infiltration and post-reaction processed. Various specificprocess options exist through which Li can be infiltrated into thecarbon scaffold 702, including:

-   -   usage of molten Li metal to initiate a reaction at exposed        carbon surfaces—assuming conditions of controlled hydroxyl group        (OH) and oxygen (O) adsorption on exposed surfaces of the carbon        scaffold 702, such as one or more        lithiophilically-functionalized surfaces that are configured to        provide Li adsorption centers, thermal oxide reduction or        exposure of the carbon scaffold 702 to above-positioned pristine        molten Li metal vapor for a duration of, for example 30 to 45        seconds at approximately 200° C., can initiate a chemical        reaction at exposed surfaces of the carbon scaffold 702 to form        a lithiophilic surface, such as LiC₆;    -   coating of exposed carbon surfaces with surface active elements        to control surface contaminants on interfacial regions of molten        Li metal and exposed carbon-fluxing elements can be used to        break oxide skull and/or facilitate melting of halogens        including fluorine (F), oxide getters can be used to reduce        oxide (Ti, other);    -   promoting alloying and wetting by coating exposed carbon        surfaces with elements, such as metals, having a lower surface        energy than Li and/or elements such as silicon (Si) aluminum        (Al) that facilitate Li wetting and/or infiltration; and    -   incorporating metal powders, or metal containing compounds, such        as silicon carbide (SiC), and others, in carbon preform, such        as, SiNP, Ni, and other, to serve as binder and facilitate        wetting infiltration allowing for the control of a ratio of        metal to carbon dependent on non-reactive wetting parameters.        FIG. 8A shows an equation for a rate of infiltration a        carbon-based structure with void spacing therein defined by any        one or more of the 3D carbon-based particles shown in FIG. 1A        through FIG. 1F, according to some implementations.

FIG. 8A shows an equation for modelling a rate of Li infiltration intoany one or more of the porous regions of the currently presentedcarbon-based structures, such as the pores 105E and contiguous pathways107E shown in FIG. 1E of the carbon-based particle 100A shown in FIG.1A. The rate of infiltration can be controlled by the non-reactiveviscous resistance of liquid metal, such as molten Li metal, followed bya chemical reaction between the liquid metal contacting the carbon toyield carbide pursuant to Washburn's equation 800A shown in FIG. 8A,where σ and η are surface tension and viscosity of liquid, respectively,θ is the contact angle and r_(eff) is the effective pore radius ofpores, such as the pores 105E shown in FIG. 1E, that can be interspersedthroughout a carbon-based scaffold, such as the carbon-based scaffold702 shown in FIG. 7. Therefore, as can be seen by the variouscoefficients used in the Washburn's equation 800A, capillary flow isdescribed by modelling the carbon-based pre-form structure as atheoretical bundle of parallel cylindrical tubes to effectivelyrepresent imbibition into porous materials.

FIG. 8B shows a non-reactive system 800B including a non-wettingconfiguration 802B and a spontaneous wetting configuration 804B,according to some implementations. For instance:

-   -   in the non-wetting configuration 802B, a pressure (P₀) is        applied to overcome capillary pressure, such as the pressure        between two immiscible fluids in a thin tube, resulting from the        interactions of forces between the fluids and solid walls of the        tube, and can be limited by viscous friction, such as that        established and characterized by the Washburn's equation 800A; L        can denote a liquid-phase Li layer, such as that provided by        molten Li metal, S can denote solid carbon surfaces exposed to        L, θ can denote the contact angle of L to S, and V can denote        viscous friction and characterized by the Washburn's equation        800A at the contact region of L to S;    -   in the spontaneous wetting configuration 804B, θ is maintained        at an angle of <60° to achieve non-reactive Li infiltration of        the carbon-based scaffold; and    -   any one or more of the non-wetting configuration 802B or the        spontaneous wetting configuration 804B can be incorporated in or        otherwise implemented in an example carbon-based scaffold 806B,        which may be a formative part of any one or more of the        presently disclosed carbon-based structures.

FIG. 8C shows a reactive system 800C including a wettable reactiveproduct layer configuration 802C and a non-wettable surface layerconfiguration 804B, according to some implementations. The wettablereactive product layer configuration 802C can involve the formation of anew 3D layer 806C similar to that discussed earlier with relation to thechemically reactive system 600B2 shown in FIG. 6B2, where the formationof the new 3D layer 604B2 or compound involves at least partialconsumption of the underlying carbon surface layer 604B2. Here the solidcarbon material S can be at least partially consumed to produce orgenerate the new 3D layer 806C which can be or include LiC₆. Incontrast, in the non-wettable surface layer configuration 804B, surfacesof S immediately facing, such as in the vertical direction, L are notreactive such that encroachment of L into capillary, tubular, openregions results in consumptive reaction with S to yield a new 3D layer808C only along those capillary open regions.

FIG. 9 shows a flowchart 900 for a method of lithiating and alloying acarbon-based structure, according to some implementations. At block 902,oxide thermal decomposition can be used to initiate surface interfacereaction by lithium (Li) vapor pressure to activate surface of carbon inpacked preform. At block 904, surface active elements compounds, in theexample of Li film infiltration into a metal substrate, can beevaporated to breakdown oxide flux and/or promote wetting. At block 906,alloying elements, such as silicon (Si), aluminum (Al), and potassium(K), can be incorporated as part of the infiltration process to promoteinfiltration/manage oxygen activity at interface.

FIG. 10A shows a flowchart for a method 1000A of preparing acarbon-based structure to undergo a lithiation operation, according tosome implementations. At block 1002A, procedures can be established fortesting lithium foil/powder preforms. At block 1004A, of proxy metalpowder preform can be used to promote non-reactive infiltration whileunderstanding reproducible protocols for managing lithium, such assurface pre-treatment/management of impurities. At block 1006A, carbonsurface activity/pre-treatment protocols can be evaluated by measuringthermal activation response through various techniques includingthermogravimetric analysis (TGA) and/or differential scanningcalorimetry (DSC).

FIG. 10B shows a flowchart for another method 1000B of preparing Limaterials suitable for usage in a lithiation operation, according tosome implementations. At block 1002B, heater platens can be calibrated,and a thermal profiling of materials can be conducted. At block 1004B, aglove box environment can be determined, such as involving conditions orsettings for moisture and oxygen before, during, and after testing. Atblock 1006B, sample can be prepared from any one or more of lithium foiland/or evaporated lithium on metal foil, carbon powder, and others.

FIG. 10C shows a flowchart for a method 1000C of nucleating a pluralityof carbon particles at a first concentration level. At block 1002C aplurality of carbon particles can be nucleated at a first concentrationlevel configured to form a first film on a sacrificial substrate, eachof the carbon particles comprising a plurality of aggregates including aplurality of few layer graphene sheets fused together. At block 1004C aporous structure can be formed based on the plurality of few layergraphene sheets fused together. At block 1006C, a molten Li metal can beinfused into the porous structure.

FIG. 10D shows a flowchart for a method 1000D of nucleating a pluralityof carbon particles at a second concentration level. At block 1002D, thecarbon particles can be nucleated at a second concentration level on thefirst film. At block 1004D, a second film can be formed based on thesecond concentration level of the carbon particles.

FIG. 10E shows a flowchart for a method 1000E of growing carbonparticles. At block 1002, carbon particles can be grown on aroll-to-roll processing apparatus.

FIG. 10F shows a flowchart for a method 1000F of evaporating the moltenLi metal. At block 1002E, the molten Li metal can be evaporated onto ametal foil. At block 1004E, the molten Li metal can be rolled from themetal foil into the porous structure.

FIG. 10G shows a flowchart for a method 1000G of preparing the anode toparticipate in a reversible migration of Li ions. At block 1002G, theanode can be prepared to participate in a reversible migration of Liions with a cathode. The cathode is prepared by any one or more ofchemical functionalization or sulfidation.

FIG. 10H shows a flowchart for a method 1000H of densifying a pluralityof graphene platelets. At block 1002H, a plurality of graphene plateletscan be densified on the void structure.

FIG. 10I shows a flowchart for a method 1000I of depositing a firstplurality of carbon particles to form a first film. At block 1002I, afirst plurality of carbon particles can be deposited to form a firstfilm on a substrate, the first film configured to provide a firstelectrical conductivity. At block 1004I, a plurality of 3D aggregatesformed of few layer graphene sheets can be orthogonally fused togetherconfigured to define a porous structure. At block 1006I, a porousarrangement can be formed in the porous structure. At block 1008I, amolten Li metal can be infused into the void structure.

FIG. 10J shows a flowchart for a method 1000J of depositing a secondplurality of carbon particles. At block 1002J, a second plurality ofcarbon particles can be deposited on the first film. At block 1004J, asecond film can be formed based on the second plurality of carbonparticles.

FIG. 10K shows a flowchart for a method 1000K of infiltrating the moltenLi metal. At block 1002K, the molten Li metal can be infiltrated in avapor phase into the void structure. At block 1004K, a chemical reactioncan be initiated between any one or more Li ions provided by the moltenLi metal and one or more exposed surfaces of the void structure. Atblock 1006K, one or more lithiophilic surfaces can be formed from theone or more exposed surfaces.

FIG. 10L shows a flowchart for a method 1000L of coating any one or moreof the lithiophilic surfaces. At block 1002L, any one or more of thelithiophilic surfaces can be coated with active elements including anyone or more of halogens and oxide getters including titanium (Ti).

FIG. 10M shows a flowchart for a method 1000M of coating any one or moreof the lithiophilic surfaces. At block 1002M, any one or more of thelithiophilic surfaces can be coated with any one or more elements havinga lower surface energy than Li including silicon (Si) or aluminum (Al).At block 1004M, a Li wetting enhancement can be facilitated of any oneor more of the lithiophilic surfaces with any one or more elementshaving a lower surface energy than Li.

FIG. 10N shows a flowchart for a method 1000N of creating a binder. Atblock 1002N, a binder can be created by incorporating any one or more ofa metal powder or a metal-containing compound including silicon carbide(SiC) into a carbon scaffold.

FIG. 10O shows a flowchart for a method 1000O of adding of a quantity ofdopants. At block 1002O, of a quantity of dopants can be at theinterface. At block 1004O, an extent of the Li wetting can be affectedcorresponding to the quantity of dopants.

FIG. 10P shows a flowchart for a method 1000P of control adsorption ofhydroxy (OH) or hydroxyl (OH) groups. At block 1002P, adsorption ofhydroxy (OH) or hydroxyl (OH) groups can be controlled at any of the oneor more exposed surfaces of the void structure.

FIG. 11A shows a flowchart for a method 1100A of Infuse lithium. Atblock 1102A, lithium can be infused by using roll-to-roll furnacebrazing or spontaneous infiltration. At block 1104A, a two-dimensional(2D) analog can be used with a 2D liquid gap filler. At block 1106A,infused lithium metal can be chemically reacted at a liquid-to-solidinterface with exposed carbon surfaces with controlled flux foractivation, increased and/or decreased surface tension, and controlledthermodynamic driving force. At block 1108A, rapid screening of lithiumwettability can be conducted with Li foil/carbon particle stacked on hotplate by using a halogen interlayer to breakdown Li₂O.

FIG. 11B shows a flowchart for a method 1100B of evaporating lithium(Li) onto a metal foil. At block 1102B, lithium can be evaporated onto ametal foil, which can act as a thermal conductor. At block 1104B, coppercan be optionally used as a current collector and/or tantalum forrelease to achieve minimal chemical interaction. At block 1106B, filmthickness can be tuned commensurate with pore volume in packedcarbon-based particles and-or structures.

FIG. 11C shows yet another flowchart for a method 1100C of preparing acarbon particle for lithiation, such as through process referred to aspre-lithiation. At block 1102C, foil on top of carbon particle packedbed or pre-lithiated and/or pre-formed can be oriented with ato-be-applied load, such as a calendar roll type, in dry roomenvironmental conditions. At block 1104C, overall isothermal-likeconditions, such as at approximately 180° C., and/or immediately belowthe Li melting point, can be created across Li and packed particles withrapid thermal spike at location of concentrated loading. At block 1106C,an exothermic reaction can be used to initiate infiltration followedwith a capillary driven fluid flow in porous carbon media takingadvantage of principles related to Darcy's law, Washburn, etc. withvariable permeability. The capillary driven fluid flow assumes noappreciable reaction product formation/build-up.

FIG. 12 shows a flowchart of a method 1200 of performing a Li infusionof a carbon particle during its formation with a vaporized Li, accordingto some implementations. At block 1202, metal, such as copper and/ortantalum, foil can be coated with lithium, such as in a vacuumevaporator; measured Li volume, such as thickness and density, can becommensurate with pore volume in packed particle layer. At block 1204,particles can be assembled into a packed film without binder, such asthrough size enlargement, creation of course granular material, such asfilm, from fines, where assembly techniques can include tumbling,pressure compaction, heat reaction, fusion, drying, agglomeration fromliquid suspensions, as well as electrostatic to form coin cell sizepucks. At block 1206, an innate carbon particle can be formed. At block1208, sp²/sp³ ratios of carbon during formation can be optimized tocorrespondingly increase lithium (Li) insertion and/or intercalation. Atblock 1210, impurity contamination, such as that caused by acetylene andother post plasma aromatics, can be reduced. At block 1212, posttreatment operations can be performed.

FIG. 13 shows a schematic diagram showing an idealized anode 1300configuration with 3D graphene-based nanostructures 1302 incorporatedtherein to provide structural definition to the anode 1300, according tosome implementations. The 3D graphene-based nanostructures 1302 can beincorporated into or provide structural definition to any one or more ofthe presently disclosed carbon-based structures, including the pores105E and/or the contiguous pathways 107E, both shown in FIG. 1E, and canconfine or otherwise retain metal dopants such as silicon (Si) 1312 andcreate surface-activated diffusional pathways 1316 to handle volumetricexpansion during Li ion 1306 alloying-de-alloying cycles, and to alsolimit electrolyte ingress. Silicon can redistribute, as shown in apathway 1310, into defects, pores, or wrinkles in few-layer graphenesheets as well as distributing, in a pathway 1308, into a binder 1304,such as highly polar polyacrylonitrile (PAN). Sulfur (S) doping can beperformed or occur at graphene 1314 to silicon contact regions orsurfaces to assist in Li complexing in Li S battery systems and relatedcharge-discharge cycles to achieve any one or more of the performancefigures quoted herein, including a specific capacity greater than 372mAh/g, which is ordinarily achievable as a theoretical maximum bygraphite alone. In some implementations, graphene oxide can be used inaddition or in the alternative to few-layer graphene, and the Li Ssystem can be immersed in a LiPF₆ liquid-phase electrolyte.

The anode 1300 can be configured with existing or to-be-developed futurecarbon-based materials, offering backward-compatibility. Thesurface-activated diffusional pathways 1316 can host Li metal, while Lican also be intercalated in between pairs of few layer graphene sheets.Pore sizes of carbon materials can be tuned in the anode 1300 to achievecertain distributions or containment levels of Li, as well as Li ionflow reversibility, and can be created with either amorphous orcrystalline carbon structures.

Pre-lithiation of the anode 1300 can initially include electrochemicalor direct contact to molten Li metal to later transition to direct vaporinfusion techniques. Carbon structures used as a formative material toconstruct the anode 1300 can be direct deposited as a film of particles,as substantially described earlier, or from powders. A rate of Lieffusion can match a rate of Li insertion within the anode 1300 to avoidexcess Li deposited or condensed carbon surfaces exposed to incoming Li.And, production and cost metric considerations of the anode 1300 caninclude:

-   -   producing carbon-based materials as low-cost powders, rather        than films, that are configured to be dropped into to existing        Li ion or Li S battery fabrications;    -   direct deposition, independent of a binder, of carbon-based        films on drums; and    -   Li infusion into carbon-based particles and structures, such as        slurry cast films/binders, evaporation techniques can be used to        purify or dry carbons.

Li infusion of the anode 1300 can include the following proceduresestablished by known roll-to-roll furnace brazing and/or spontaneousinfiltration techniques, including any one or more of the following:

-   -   use a two-dimensional (2D) analog with 2D liquid gap filler;    -   liquid to solid chemical reactions, using flux for activation;    -   increase of a proportion of solid to viscous surface area and        decrease a proportion of liquid to viscous surface area to        control and tune surface tension and/or thermodynamic driving        forces; and    -   screen Li wettability with Li foil/carbon particle stack on a        hot plate using a halogen interlayer to breakdown any formed        lithium oxide (Li₂O).

Li infusion of the anode 1300 can also include the following procedures,techniques, or implementations related to the evaporation of Li onto ametal foil configured to act as a thermal conductor:

-   -   selection of copper (Cu) for use as current collector in Li ion        or Li S battery systems incorporating the anode 1300;    -   tantalum (Ta) interspersed within the anode 1300 for Li ion        release resulting in minimal overall chemical interactions; and    -   production of carbon-based film thicknesses commensurate with        pore volume in packed particles.

Moreover, Li infusion of the anode 1300 can also include the followingprocedures, techniques, or implementations related to the orienting ofLi and Ta foil on top of a carbon particle packed in a bed configurationthat can be prepared to receive a load or pressure provided by arotating calendar roll type drum in dry room environmental conditions:

-   -   forward rotation of a calendaring roll or drum wrapped with a        layer of Ta foil that is further wrapped in Li foil compresses        against carbon particles prepared as a thin layer of material,        which is placed on a copper foil, with heat applied by the        calendaring roll and to the Cu foil to melt Li and create molten        Li metal that infiltrates into the carbon particles;    -   creation of overall isothermal conditions, such as at        approximately 180° C., just below the Li melting point across        infiltrated Li and packed carbon particles;    -   observing a rapid thermal spikes at location of concentrated Li        loading; and    -   Li infiltration with an exothermic reaction with capillary        driven molten Li metal fluid flow in porous carbon media as        governed by any one or more of Darcy's law, Washburn's equation,        etc., with variable permeability, processes assume no        appreciable reaction product formation or build-up.

Still further, Li infusion of the anode 1300 can also include thefollowing procedures, techniques, or implementations:

-   -   coat metal, such as copper (Cu) and/or tantalum (Ta) foil with        lithium Li in a vacuum evaporator; control Li volume, such as        thickness and density, commensurate with pore volume in a packed        carbon particle layer or film;    -   assemble carbon particles into a packed film without a binder,        although binder options could be considered assuming there is        not interaction with molten Li and that the proposed binder        could be easily removed after Li infiltration;    -   enlargement and/or creation of course granular carbon material,        such as a film, from carbon fines, such as by tumbling, pressure        compaction, heat reaction, fusion, drying, agglomeration from        liquid suspensions, as well as electrostatic to generate coin        cell size structures shaped as pucks;    -   collecting or screening any of the aforementioned materials        within a reactor;    -   performing post microwave sintering, or fusing; and    -   performing partial compaction into a puck or tablet independent        of a carbon die.

Innate carbon particle formation of few layer graphene and other carbonsused to form the anode 1300 can include:

-   -   optimizing sp² and/or sp³ carbon structure formation to increase        lithium insertion/intercalation; and    -   reducing impurity contamination, such as acetylene and other        post plasma aromatics.

Post treatment methods can include:

-   -   washing, such as removing aromatics;    -   baking carbons for a duration of approximately 3 hours at        approximately 500° C. to remove adsorbed moisture and/or oxygen;        and    -   nitriding and/or treating carbons with silicon monoxide.

Factors influencing Li infiltration into carbon structures of the anode1300 can include:

-   -   precursor volume;    -   melt temperature, such as from approximately 180° C. to 380° C.;    -   particle post treatment, such as at a carbon surface exposed to        contact with Li;    -   mechanical pressure;    -   graphene properties, such few layer, or sheet size;    -   carbon structure morphology, including pore size, volume,        distribution; and    -   surface activation.

Carbon structure response to Li infiltration can include:

-   -   spontaneous infiltration;    -   accumulation of excess Li material to achieve a balanced mass        proportionate to Li input; and    -   extent of infiltration based on the ratio of carbon surface area        exposed to incoming Li compared against the overall volume of        the carbon structure.

FIG. 14 shows a silicon and carbon (Si—C) anode performance comparinganode specific capacity in mAh/g over charge-discharge cycle number,according to some implementations. The various series shown including426, 459, 462, 486, 487, and 401 can include variants and/orpreparations similar to the anode 1300 shown in FIG. 13 or any one ormore of the carbon structures shown in FIG. 1A through FIG. 1Fincorporated within a Li ion or Li S system anode. As shown, thepresently disclosed carbon structures can uniformly yield specificcapacity values significantly higher than 372 mAh/g as commonlyassociated with a graphite anode.

FIGS. 15 and 16 show schematic diagrams related to an idealized cathodeconfiguration 1500, shown in FIG. 15, featuring dispersed lithiumsulfide (Li₂S) nanoparticles in graphene sheets held together by a PANtype binder and submerged in LiTFSI electrolyte solution to providefacile Li ionic transport and electric conduction as well as mitigationand control of polysulfides (PS) generated in Li S battery systemcharge-discharge cycles, according to some implementations. Theidealized cathode configuration 1500 can be implemented at least in partwith any one or more of the presently disclosed carbon structures,including to form the pores 105E and/or contiguous microstructures 107Eshown in FIG. 1E, in Li S battery systems. FIG. 16 shows an examplein-situ 3D nanostructured few-layer graphene material 1600, which may beincorporated to provide structural definition to any one or more of thepresently disclosed carbon structures. In some implementations, a stackof few-layer graphene sheets 1602 can include milled, sulfur impregnatedgraphene heated at a two-stage high temperature (HT) process to 250° C.and 350° C. The stack of few-layer graphene sheets 1602 can beinfiltrated by Li such as that provided by lithium triethylborohydride(LiEt₃BH) in THF solution or n-butyllithium provided in an inert argon(Ar) atmosphere to provide a Li source 1604 by any one or more of theaforementioned Li infiltration techniques. The Li infiltrated stack offew-layer graphene sheets 1602 can undergo HT vacuum treatment at 10hours at 110° C. to in-situ form Li₂S in pores, such as the pores 105Eshown in FIG. 1E, where such Li₂S is involved in Li S electrochemicalcell functioning as described earlier.

FIG. 17A shows an enlarged perspective cut-away view of carbon-basedparticle 100A, 100E and/or the like. Individual ligaments 1702A formedfrom as discussed in connection with carbon-based particle 100A shown inFIG. 1A through FIG. 1E, contact surfaces and/or regions betweenelectrically conductive interconnected agglomerations of graphene sheets101B, may extend to form a lattice and/or tree-like branched structureof section 1700A through which Li ions (Li+) 1704A may be intercalated,inserted in between individual gradient layers of section 1700Acomprising, 3D bundles of graphene sheets 101B. Electric current may beconducted via flow of electrons through contact surfaces and/or regionsbetween interconnected 3D bundles of graphene sheets 101B. Li ions, mayflow through pores 1710A, sized at a larger size of the bi-modaldistribution of voids or pores as described in FIG. 1A through 1E on theorder or 20 to 50 nanometers, or be confined, such as via chemicalmicro-confinement, in pores sized generally on the order of 1 to 3nanometers.

Therefore, Li ion flow may be finely controlled or tuned in carbon-basedparticle 100A to, for example, to be diametrically opposite to electronflow as needed to facilitate an electrochemical gradient that may benecessary for electricity conduction and/or electron flow throughcontact points and/or regions of 3D bundles of graphene sheets 101B.Spacing between individual carbon-based ligaments may be set at 0.1 μm.Those skilled in the art will appreciate that the dimension of 0.1 μm isprovided as an example only and that other suitable similar ordissimilar dimensions may exist in section 1700A of carbon-basedparticle 100A.

Section 1700A may be formed of 3D bundles of graphene sheets 101B thatare sintered together with each other to form a configuration wherethere are no completely open channels such that electricity isnecessarily conducted through contact points and/or regions ofinterconnected 3D bundles of graphene sheets 101B. Thus, liquid passingthrough voids 1704A and the conductive nature of carbon-to-carbonbonding facilitates a connection of carbon-based materials to othercarbon-based materials without the necessity of a chemical binder and/orchemical binding material or agent, many of which resulting inundesirable chemistries or side effects regarding functionality ofcarbon-based particle 100A.

Open porous scaffold 102A of carbon-based particle 100A presents adeparture from traditional industry-standard battery electrodes that mayinvolve slurry-cast boulders, relatively large particles, organizedhaphazardly on a substrate, such boulders typically requiring a binderto be held together to conduct electricity there-through. Open porousscaffold 102A defined by hierarchical pores 101A and/or the contiguousmicrostructures 107E of carbon-based particle 100A allows for improvedelectrical conduction therein.

FIG. 17B shows the carbon-based particle of FIG. 17A withgraphene-on-graphene densification. For the example of FIG. 17B,surfaces 1700B shown in FIG. 17B and/or surfaces 1708A shown in FIG. 17Aat edge regions, at least partially planar surfaces of the branched,tree-like structure of section 1700A of carbon-based particle 100A, maybe densified upon the application, deposition, or otherwise growth ofmultiple additional graphene layers. Such densification processes,methods and/or procedures permit for the creation of intricate,multi-layer, and potentially nearly infinitely tunable 3D carbonstructures comprising combinations of 3D bundles of graphene sheets101B. Accordingly, such fine tunability accomplished bygraphene-on-graphene densification may facilitate the attainment ofparticular electrical conductivity values when carbon-based particle 100is integrated into an electrode of a battery.

FIG. 18A through FIG. 18C show real-life micrographs 1800A, 1800B, and1800C, respectively, of any one or more of the presently disclosedcarbon structures, include the carbon-based particle 100A and/or thecontiguous microstructures 107E shown in FIGS. 1A and 1E, respectively,at various increasing levels of magnification.

FIG. 18D shows a micrograph 1800D with a composite carbon agglomeratehaving an internal structure similar to that described for carbon-basedparticle 100A, complete with pores 105E and contiguous microstructures107E, and has been prepared both in size and composition forincorporation in a cathode for Li ion systems, but can also beapplicable to process and produce cages for Li on an anode. Randomlysized and shaped agglomerates can be used to fabricate any one or moreof the presently disclosed electrodes. Nevertheless, tuning procedurescan allow for the production of carbon agglomerates and/or particles atregular expected sizes as well, potentially providing for both ease ofhandling and advantages in processing.

FIG. 18E shows a micrograph 1800E with an activated carbon structure forinfiltration with sulfur (S) used in a Li S system cathode as describedby at least any one or more of the presently disclosed carbon basedstructures, including the contiguous microstructures 107E shown in FIG.1E. The activated carbon structure for infiltration with sulfur (S)shown in micrograph 1800E can be produced by a combined screw conveyorsystem or through other distinct steps. Thermal reactor producedmaterial has been shown to be more lithiophilic than un-doped and/orun-functionalized microwave-generated carbon structures. In someimplementations, the prevalence of organic and/or hydrocarbon-basedcontamination on the surface of few layer graphenes produced in thereactors may demand the performance of additional post processingrefinement steps.

FIG. 19A shows a schematic depiction 1900A of a 3D graphene-particlecathode scaffold, such as carbon scaffold 300B featuring sulfur (S)micro-confinement therein, suitable for scale-up and/or incorporationwith any one or more of the carbons presently disclosed, including usageas a formative material to produce contiguous microstructures 107E shownin FIG. 1E. In the example of FIG. 19A, graphene-based sheets and/orstructures containing sulfur entrainment and/or confinement 1902A invarious 3D cathode scaffolded structures or configurations, of variousthicknesses 1904A and 1906A, are shown. S inclusion in graphene-basedbattery chemistry provides desirable electric charge storage andretention measured in milliamp hours, further described by the synthesisof a graphene-sulfur composite material by wrapping poly(ethyleneglycol) (PEG) coated submicrometer sulfur particles with mildly oxidizedgraphene oxide sheets decorated by carbon black nanoparticles.

The PEG and graphene coating layers are important to accommodatingvolume expansion of the coated sulfur particles during discharge,trapping soluble polysulfide intermediates, and rendering the sulfurparticles electrically conducting. The resulting graphene-sulfurcomposite showed high and stable specific capacities up to ˜600 mAh/gover more than 100 cycles, representing a promising cathode material forrechargeable Li batteries with high energy density. Other studies haveshown that activated graphene (AG) with various specific surface areas,pore volumes, and average pore sizes have been fabricated and applied asa matrix for sulfur. The impacts of the AG pore structure parameters andsulfur loadings on the electrochemical performance of Li-sulfurbatteries are systematically investigated.

The results show that specific capacity, cycling performance, andCoulombic efficiency of the batteries are closely linked to the porestructure and sulfur loading. An AG3-sized (S) composite electrode witha high sulfur loading of 72 wt. % exhibited an excellent long-termcycling stability at 50% capacity retention over 1,000 cycles andextra-low capacity fade rate (0.05% per cycle). In addition, when LiNO₃was used as an electrolyte additive, the AG3/S electrode exhibited asimilar capacity retention and high Coulombic efficiency at ˜98% over1,000 cycles. The excellent electrochemical performance of the series ofAG3/S electrodes is attributed to the mixed micro/mesoporous structure,high surface area, and good electrical conductivity of the AG matricesand the well-distributed sulfur within the micro/mesopores, which isbeneficial for electrical and ionic transfer during cycling.

FIG. 19B shows a 3D few-layer graphene anode scaffold, such as carbonscaffold 300 and/or lithiated carbon scaffold 400A prepared forincorporation within or usage as a formative material for a Li ion or LiS system anode with Li intercalation between graphene layers. In theexample of FIG. 19B, Li ions (Li+) are shown in various configurations1900B including as being intercalated into FLG 1902B and reversibleinclusion of Li metal in a carbon-based host scaffold 1904B. Liintercalation into bi-layer graphene may relate to and address the realcapacity of graphene and the Li-storage process in graphite, whichpresent problems in the field of Li ion batteries.

Corroborated by theoretical calculations, various physiochemicalcharacterizations of the staged lithium bilayer graphene productsfurther reveal the regular Li-intercalation phenomena and thereforefully illustrate this elementary lithium storage pattern oftwo-dimension. These findings not only make the commercial graphite thefirst electrode with clear lithium-storage process, but also guide thedevelopment of graphene materials in Li ion batteries. Li absorption andintercalation in single layer graphene and few layer graphene differs tothat associated with bulk graphite. For single layer graphene, thecluster expansion method is used to systemically search for the lowestenergy ionic configuration as a function of absorbed Li content. It ispredicted that there exists no Li arrangement that stabilizes Liabsorption on the surface of single layer graphene unless that surfaceincludes defects. From this result follows that defect poor single layergraphene exhibits significantly inferior capacity compared to bulkgraphite.

In some implementations, carbon-based particle films can include atleast the following particle-like properties, in addition to any one ormore of: sacrificial, as well as, supporting film substrates; tunablevelocity to substrate; tunable impact energy from implantation toadsorption; tunable thickness; and, tunable porosity; any one or more ofwhich can be integrated with additive type manufacturing capability.

In some implementations, any one or more of the presently disclosedcarbons and carbon-based structures can enable significant batteryperformance advantages over currently available Li-ion and/or Li Sbatteries, including: to achieving any one or more of the physicaland/or electrical energy storage and/or conductivity values including anenergy density in the range of approximately 400 to 650 (W·h)/kg, with amaximum theoretical value of 850 (W˜h)/kg, and also including aspectswith a sulfur and/or sulfur-intercalated cathode of 650 (MAh)/g, and,aspects of the graphene sheets 102A and/or conductive carbon particlesinterspersed therewith to define pores and/or voids, etc., assubstantially discussed in connection with that shown in FIG. 1A throughFIG. 1E, with ionic Li (Li+) intercalated therein to ultimatelyachieving an energy density storage value of 900 to 2,000 (mAh)/g.

FIG. 20A shows cathode specific capacity levels over cycles and variousrepresentative sulfur-nano confinement as representative of applicationand/or usage of systems based on or using carbon-based particle 100A andderivatives thereof diagrams and images. Improved cathode specificcapacity, electrode level, as measured in mAh/g, is shown in graph 2008a for various compositions and/or compounds, any one or more of which atleast partially include carbon-based particle 100A formed with sintegrated therewith to enhance cathode specific capacity.

FIGS. 20B and 20C show charts regarding accelerated carbon tuning tomitigate polysulfide (PS) shuttle related issues, indicating thatincreasing the porosity of carbon-based materials, carbon-based particle100A and variations thereof, reduces PS shuttling, defined as wheresulfur S reach the negative electrode surface and undergo chemicalreduction, leading to unwanted automatic electrochemical cellself-discharge. Chart 2002B shown in FIG. 20B shows a mean intensitychange of low porosity carbon generally at higher levels than highporosity carbon. Chart 2002C shown in FIG. 20C shows high porositycarbon generally with higher levels of percentage capacity retentionover repeated battery usage cycles relative to low porosity carbon.

Tuning of carbon-based particle 100A may achieve more efficientfabrication including Li utilization and potential increase the rationof active material to inactive material within a battery electrode,binder reduction, improved uniformity and controlled electrochemicalreactions, such as battery electricity conductivity and/or activity.Parameters of carbon-based particle 100A can be tuned to achievespecific performance features as a function of the percentage of Liloading per unit area or volume of carbon-based particle 100A,including:

-   -   at low loading levels, less than capacity, compensating for        first charge losses/more effective SEI formation; at        saturation/matched loading, Li rich regions, galvanically        coupled to carbon,    -   oxidizing materials when in contact with electrolyte and        insertion of Li and/or Li-ions via intercalation between        graphene layers;    -   at excess loading levels, metallic Li is infiltrated into        engineered host carbon; configuring the host to serves to        accommodate/stabilize expansion of Li and suppress dendrite        formation as a result of increased Li surface area, enables        specific capacities commensurate with pure Li: >2,000 mAh/g;        and,    -   preparing Li ion processes/methodology directly transferable to        lithium ion hybrid capacitors.

Ongoing challenges, related to the thermal and/or liquid infusion of Liand/or Li ion into carbon-based structures such as carbon-based particle100A as outlined in listing 2900E can include management of Lireactivity regarding surface tension, wettability at a solid-to-liquidelectrolyte interface; management of capillary Li and/or S infiltrationkinetics, engineering of electrical gradient through electrodethickness, gradation of Li infiltration such that it is highest atcurrent collector and transitions to a more ionic conductingconcentration and/or level at electrolyte interface, and, the carefullytuned engineering of surface chemistry by facilitating stable SEIformation in contact with electrolyte and minimize reactivity with air.

Disclosed aspects may build upon traditional two-dimensional (2D)plating, that may be similar to brightening agents in electroplating. Inelectroplating, the addition of chemical additives may often increasepolarization, decrease current density; such as, redirect currentdensity to low as opposed to high areas, such as protrusions; produce arelatively high nucleation rate, and result in a moderate chargetransfer rate. In the context of plating or stripping for battery chargeand discharge cycles, for batteries with electrodes equipped withcarbon-based particle 100A as shown in FIG. 1A through FIG. 1E, carbonfilm may serve as a flexible support for SEI formation as well as,redirecting current density to low, as opposed to high, areas.

Employed herein in a context of producing carbon-based particle 100A andintegrating it with a Li ion battery, cementation may be employed in anyone or more of the disclosed fabrication techniques. Cementation impliesa process of altering a metal by heating it in contact with a powderedsolid, precipitation in copper production may refer to and/or involve aheterogeneous process. Such a process may imply conditions wherereactants are components of two or more phases, such as solid and gas,solid and liquid, two immiscible liquids, or in which one or morereactants undergo chemical change at an interface, on the surface of asolid catalyst, in which ions are reduced to zero valence at a solidmetal surface, such as, Cu ions on Fe particle surface; and, where ironoxidizes and copper is reduced, such as copper being relatively higheron a galvanic series, similar to Li versus C.

Molten metals including Li metal can be managed for welding such thatany one or more of the mentioned techniques can be functionallyintegrated with and/or used to produce carbon-based particle 100A toenhance Li ion or Li S battery performance. Such ancillary processesand/or techniques include: management of reactive metals via welding;classic metal inert gas (MIG), gas tungsten arc welding (GTAW) alsoreferred to as tungsten inert gas (TIG) and submerged arc welding (SAW)to utilize inert shielding gas to join reactive metals, such as Ti andAl, through a liquid metal process, such as by welding. Examples includeusing inert shielding gas to form liquid pools of reactive metal withoutoxidation, where delta Gf of oxides, such as TiO₂, Al2O₃, is on par withthat of Li₂O. Through controlled use of inert shielding gas aroundreactive metals, oxygen and moisture may effectively be managed in thepresence of reactive liquid metals. In such environments and conditions,liquid Li can be infiltrated into the carbon-based structures ofcarbon-based particle 100A through controlled shielding gasconfiguration and operation.

FIG. 21 shows Raman spectra for 3D N-doped FL graphene includingcharting for both pristine carbon and N-dope carbon. In the example ofFIG. 21, Raman spectra for 3D N-doped FL graphene 2100 includes 2D peak2102 at approximately 2730 cm−1 and D peaks 2104, 2106 at approximately1600 cm⁻¹ and 1400 cm⁻¹, respectively.

FIG. 22 shows various properties associated with bilayer graphene 2200.In the example of FIG. 22, a sample bilayer graphene infrastructure 2200is shown with two layers of graphene oriented in the position shown,understood as devices which contained just one, two, or three atomiclayers. Schematic 2202 shows approximate spacing measurements of 1.42 Å,1.94 Å and/or 3.35 Å between individual graphene sheets. Schematic 2204shows various example defective sites 2206 and/or 2208 what may occurwithin a defined vicinity of an edge plane and/or assist with thecreation of carbon-based particle structures including one or moregraphene sheets. Schematic 2210 shows various model diagrams 2212 of atop view of a hard-sphere carbon-particle model.

In some implementations, reactor tuning can be performed to, forexample, any one or more of: increase FL graphene spacing, reduce Vander Waal forces; control doping; promote carbon vacancy formation; and,decreases Li adsorption energy and/or increase Li capacity. Li ionintercalation may, for example, shift graphene sheet stacks from an A-Bconfiguration to A with intercalation accommodated by increased spacing,where, for example, in graphite, A-A may shift back to A-B withde-intercalation; and, in FL graphene, in FL graphene, AA stackingremains with de-intercalation, such as by maintaining increased spacing.Such stacking configurations may be associated with the carbon-basedparticle 100A shown in FIG. 1A through FIG. 1E.

FIG. 23 shows an illustrative flowchart for depicting an exampleoperation 2300 for preparing a 3D scaffolded film containingcarbon-based particles. In the example of FIG. 23, method 3300 includespreparing a 3D scaffolded film containing carbon-based particles thereinat operation 2304 by providing the 3D scaffolded film to a roll-to-rollprocessing device or apparatus at operation 2306. Carbon rich electrodesmay be deposited on the 3D scaffolded film at operation 2308; and,processing the 3D scaffolded film on the roll-to-roll processing deviceor apparatus independent of application of chemically inactive bindingmaterials may occur at operation 2310 prior to conclusion of the method2300 at operation 2312.

In the foregoing specification, the disclosure has been described withreference to specific examples. It will however be evident that variousmodifications and changes may be made thereto without departing from thebroader spirit and scope of the disclosure. For example, theabove-described process flows are described with reference to aparticular ordering of process actions. However, the ordering of many ofthe described process actions may be changed without affecting the scopeor operation of the disclosure. The specification and drawings are to beregarded in an illustrative sense rather than in a restrictive sense.

1. A lithium (Li) ion battery comprising: an anode; a cathode positionedopposite to the anode; a porous separator positioned between the anodeand the cathode; and a liquid electrolyte in contact with the anode andthe cathode, the anode comprising: an electrically conductive substrate;and a first film deposited on the electrically conductive substrate, thefirst film comprising a first concentration of carbon particles incontact with each other and configured to define a first electricalconductivity for the first film, each of the carbon particles comprisinga plurality of aggregates formed of few layer graphene (FLG), theplurality of aggregates forming a porous structure configured to undergoa lithiation.
 2. The Li ion battery of claim 1, wherein the lithiationincludes any one or more of an intercalation operation or a platingoperation.
 3. The Li ion battery of claim 1, wherein each of the anodeand the cathode comprises an electroactive material.
 4. The Li ionbattery of claim 1, wherein the porous structure is configured toprovide electrical conduction between contact points of at least two ormore graphene layers within the FLG.
 5. The Li ion battery of claim 1,wherein the porous structure is configured to contain a molten Li metal.6. The Li ion battery of claim 1, wherein the porous structure isconfigured to receive the liquid electrolyte.
 7. The Li ion battery ofclaim 1, wherein the liquid electrolyte is configured to facilitatetransport of a plurality of Li ions within the porous structure.
 8. TheLi ion battery of claim 1, further comprising a second film deposited onthe first film, wherein the second film comprises a second concentrationof carbon-based particles.
 9. The Li ion battery of claim 8, wherein thesecond concentration of carbon-based particles is configured to providea second electrical conductivity for the second film that is lower thanthe first electrical conductivity.
 10. The Li ion battery of claim 3,wherein the electroactive material resides in pores of one or both ofthe anode and the cathode.
 11. The Li ion battery of claim 3, whereinthe electroactive material has a specific surface area (SSA) betweenapproximately 1,635 m²/g and 2,675 m²/g.
 12. The Li ion battery of claim3, wherein the electroactive material comprises any one or more ofpre-lithiated few layer graphene (FLG), pristine graphene, grapheneoxide, reduced graphene oxide, graphene fluoride, graphene chloride,graphene bromide, graphene iodide, hydrogenated graphene, nitrogenatedgraphene, boron-doped graphene, nitrogen doped graphene, chemicallyfunctionalized graphene, physically or chemically activated or etchedversions thereof, sulfur-doped graphene, or electrically conductivepolymer coated or grafted versions thereof.
 13. The Li ion battery ofclaim 1, wherein the porous structure is defined by the aggregatesindependent of a binder.
 14. The Li ion battery of claim 1, wherein theporous structure is configured to be formed in a substantially sphericalshape.
 15. The Li ion battery of claim 14, wherein the porous structurein the substantially spherical shape has a dimension in any one or moreof in the range of 1-30 μm, <50 μm, or above 500 nm.
 16. The Li ionbattery of claim 1, wherein the porous structure comprises an active Liintercalating structure configured to incorporate silicon (Si), theactive Li intercalating structure having a specific capacity of betweenapproximately 730-3,600 mAh/g.
 17. The Li ion battery of claim 12,wherein the chemically functionalized graphene includes a functionalgroup selected from quinone, hydroquinone, quaternized aromatic amines,mercaptan, disulfide, sulfonate (—SO₃), transition metal oxide,transition metal sulfide, or a combination thereof, including functionalgroups configured to react with or incorporate any one or more ofmagnesium (Mg), calcium (Ca), aluminum (Al), strontium (Sn), and zinc(Zn).
 18. The Li ion battery of claim 1, wherein the electricallyconductive substrate is a current collector. 19.-22. (canceled)